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THE 



PHYSIOLOGY OF MAN; 



DKBIQNED TO BXFBX8Zin 



THE EXISTING STATE OF PHYSIOLOGICAL 

SCIENCE, 



Aa Amao 



TO THE FUNCTIONS OF TEE HUMAN BODY. 



St 

AUSTIN FLINT, Jr.. M.D.. 

FKoratooa or ranmhoni Atm psTBioLooirAi. anatomt ih Tin BKLLivm noapiiAi. 

NIDICAL COLLBaB,VI» TOBK : FELLOW Or TBBNIW TOHK AI^ADBMT Or 

motctKi; HMBm or thb medical botibtt or nis 
couifT* or itKw Towc, txQ^ ko. 



IS HTE TOLCMIS.-VOL, I. 
INTBODTJOTION; BLOOD; OIECm.ATION; RESPIRATION. 

BXCOND SDmOir, RZnSgD AtTD CORRSCTSD, " ~ " 



NEW YORK: 
D. APPLETON AND COMPANY, 

649 & 561 BROADWAY. 
1ST5. 




fc'iTPtETOlfft-CO, 

lu th« Cicrk'i Office of tlie DUUlct Court of the ntil(«d Statoi for tba dutHhein I'ti-trlot 

ofNcr. rork. 



F (cpz.fi 

V.I 



TO 



CHARLES ROBIN, 

Tea RUT psomsoK or Euroi-oaT n tki rACTLTT or imiicm or ruts, 



AS A TOKBS or APPBK0IATIO5 OF THB 

KUMSBOCB ORIonfAL BBSEABOHXS AHD DISOOTBRIBS, 

PABTIOnLABLT IN 

HlfiTOLOOT AEID FHTSIOLOQIOAL CHSMISTRT, 

b\ wmOH HB HAS OOMTBIBUTED SO LABOELT TO BRtSQ THE B0IE5CS OF 

PHTSIOLOQT TO ITS PBB8INT OOSDmoH, 

AND IN 

QRATSFTTL BBUEMBBANOB OF KANT ACTS OF FBIXNDBHir, 

Tme WOBK IS INSOBIBEB BT 

TffE AUTHOR. 



PREFACE. 



In entering upon the labor incident to the preparation 
of a work purporting to treat comprehensively of the pbjsi- 
ology of man, the author appreciated the magnitude of the 
undertaking ; and the special study which it necessarily de- 
manded has not diminished that diffidence with which a 
student of any of the natural sciences puts forward a book 
which he hopes may add somewhat to existing knowledge, 
or fairly represent what is known in any particular depart- 
ment. In assuming so grave a responsibility, the author 
should be actuated by a sense of peculiar fitness for his task, 
as well as a conviction that literature demands such a work 
as be proposes to writa. Without assuming these good and 
sufficient reasons, the author of the present volume pleads an 
earnest desire to advance the science of physiology and facili- 
tate its study ; and he indulges the hope that he may be in- 
strumental in making the student and practitioner of medi- 
cine better acquainted with what must be conceded to be the 
basis of true pathology, and interest, to some extent, the gen- 
eral reader in the all-important subject of human physiology. 

The plan of the present work involves a consideration ol 



6 



FB£FACC. 



pore Iiuiiian jjliyslolojry, and will embrace pLysiological 
uhoiiistrv and the auatomj of tlio tissnea and orgatie. of tlio 
bodj, only bo far as necessary for the elucidation of the func- 
tions of the organiera. Though, undoubtedly, the ohemistry 
and general anatomy of the tissues and orgauB strictly belong 
to phjsiolog;y, they present many points which have no benr- 
U)g, that we are as yet able to comprehend!, upon the tiinc- 
tiona. In the present condition of the science, a considera- 
tion of these ■would only encumber and obecure the history 
of the physiological proceeaea. While it is nndouhtedly true 
that every advance in pliysiological chemistry or histology 
will have its bearing, sooner or later, upon physiology, it is 
evident that diseoveriee in these departments roust be multi- 
plied and coordinated Ijeforo their relations to the functions 
can be iiiUy appreciated. Until then they are specially inter- 
esting only in a chemical and anatomical point of view. In 
the same way every discovery in physiology, QO matter how 
unimportant it may at first appear In a practical point of 
view, ■will eventnaUy have its bearing upon practical medi- 
cine, sargery, or obstetrics; yet it will not find its way into 
works on tho&e Bubjecta until ita relations become apparent. 

As ftu introduction to the study of physiology proper, a 
certain amount of knowletlge of phyaiologieal cLemi&try is 
indispensable. It is in this direction that we are to look for 
advances which will enable us to comprehend the proceeiica 
of nutrition, the end and object of all the vegetative fuiiclions 
of the body. Tlie introduction, then, is devoted to pliysiolog- 
ical chemistry* No attempt Las been made to treat of this 
sabjoet eshaustively, or to include a consideration of all the 
proximate principles which have been isolated and etndied. 
Aathe general propertiea and relations of the different clasbes 



PHEFACE. 



of proximate principles are bj far the inoet important to us as 
physio logiata, these Imve been specialty dwelt upon, and 
their relatione to nutrition fulLowed out as eooipletely aa 
poesible, with our present knowledge, A coneideration of 
the excrementitious proximate principles, bein^ connected 
tdneively with escretion, has been deterred, to be taken up 
connection witli that function. 

In treating of physiology proper, it has been the design 
of the author to present what is actually known regarding 
the functions of the body; and in order to fnciiitate their 
study, he has generally eommonced the consideration of in- 
dividual functioDB with a sketch of the physiological anat- 
omy of the parta. This ia the natural point of departure In 
the thorough investigation of any special function. 

The science of physiology dates" from the earliest periods 
in the hiatory of medicine; and certain important physio- 
logical facta were demonstrated experimentally hundreds of 
jeais ago. While the author haa regarded purely historical 
considerations, and diecnifiions of mere theoretical {questions, 
aa unprofitable, he has attempted to give due credit to those 
who, by their experiments and obeervationB, have contributed 
to bring the wienco to its preacut condition. With this view, 
be has procured and consulted, as far as possible, accounts of 
original invcBtigations; but from the poverty in physiologi- 
cal works of the public libraries to which he has had access, 
it hfis been necessfiry to depend to a certain extent on the 
exhaustive treatises on physiology published in other conn 
tries. Though, undoubtedly, he haa been unable in all in 
stances to give due credit to every observer, this has been 
attempted aa far as poeaible. 

It is an undoubted fact that nearly all the irapurtmit 



6 



F&EFACE. 



devetopmeDts in pbrsiologj have been tlie result of experi- 
ments tJpoa living animala, by vitisections or otherwise, or 
accurate experimental observations npon tbe Lnman eobject. 
The great extension of tbis metbod of fctudy is the can^e of 
the rapid advances tbe science 19 making at tbe pre&ent daj. 
For some years the antbor has been in tbe habit of employ- 
ing viviBections in public tenching, and in this way has fre- 
qnently verified tlie obeerrationBof tbe earlier as well as tbe 
more modem phjaiologista, A frequent repetition of esperi- 
inentB has often enabled him to reconcile tbe discordant ra- 
Bultsof the obflervationa of others; and following out new 
queetiona which bare presented themE<elTes in the constant 
observation of tbe living organs, he has advsaced some 
original viewa regarding certain of tbe fanctiona, A new 
method ib likewUe presented for tho analvBiB of the blood 
with reference to its organic constituents. 

The pUu of publieatiou of tbe present work h one which 
Ib novel in thia country, but which baa been adopted abroftU 
in almost all elaborate treatiftes on physiology. It is pub- 
lished in fire volumes, each, however, forming a distinct 
treatise devoted to natural subdivisions of tbe subject. 

New Tdik, October, I8B([. 



In preparing a second edition of thia volume, the whole 
has been wirettdlj revised and corrected, aud numorous al- 
tei-fttiona have been made. The hiator}- of the discovery of 
the L"ircnIation, and the chapters on tbe blood, have been 
enttroly rewritten. The remaining voliimoa have not been 
found to require such extensive revision. 

Nit Tout, Januat v, 1 S7S. 



GONTElsrTS. 



INTRODUCTION. 



G«nenl considerations — Phjrsiological properties oforguiixed strncturee — Prozi- 
mate principles — Inoi^anic principles — Organic non-nitrogeniied principles 
— Organic nitrogenized principles, Page 18 

CHAPTER L 

THK BLOOD. 

General considerations — Transfusion — Quantity — General characters — Opacltj 
— Temperature — Specific graTity — Color — Blood-corpuscles — DeTelopment 
of the blood-corpuscles — Leucocytes, or white corpuscles — Derclopment of 
leucocytes — Composition of the red corpuscles — Globuline — Hsmaglo- 
bine, 9S 

CHAPTER n. 

coxposinoH or thi blood-plasha. 

Analysis of the blood for fibrin, corpuscles, and albumen — Composition of the 
blood-plasma — FUsmioc, fibrin, mctalbumcn, and serine— Peptones — Color- 
ing matter, 181 



CHAPTER III. 

COAOtrtATIOB OF TRK BLOOD. 

General considerations — Characters of the clot — Characters of the semm — Co- 
agulating principle in the blood — Circumstances which modify coaji^uUtion — 
Coagulation of the blood in the organism — Spontaneoas arrest of hemor- 
rhage — Cause of the coagulation of the blood — Paraglobulinc, or fibrino- 
plasUo matter — I'ibrtnogen — Summary of the properties and fuDctions of 
the blood 140 



to 



CONTEXTS. 



CHAPTER IV. 

OIBOCTUlTtOn 07 TUB BLOOD. 

Discovery of the cireiilMion — Phj-aiotopcii] anaJomy of the heart — TalroB of the 
Lieart — Mov-emenia of thi* heart — IcetpiilsEi of the liCAtt — >Succ(s?)oil of mtire- 
menta of the henrt — Force of thi h<-ai't — Action of tbe vb1vc*-=8oiuiJ3 of the 
tiiMrt— Caiiae of the aaofidd of ih* lieurt, .... P«ge 170 

OHAPTER V, 

VREgCKNCT OF THS HKAKT's AtTTlOK, 

Fi-cquenCy of the hearfa action. — InSiience of age— InSiicnce of digestion — luflc^ 
COM of posture and muRcular CKtrtioo — InQuenco of cuyrc'iae — lulEuvuca of 
teiopemturo— Influenoe of rirspiration on tlie action of the liearl— Cuuso of 
the FliytlimionJ contntclions of the hiinrt^Enflucnce of the nervous tijatum PD 
tbuheurt — ClriaioDof die pai;uaiuga3tn(» — (iiilva&iudDri of tha pnciimogBS- 
trii.-i — Cmisiia of the arrcikt of xctipa of Qm bcut — Bbn& upon Uio cpigtio- 
Uium, fill 

CHAPTER VI, 

0U01IU.TI0tf OP TBS Bi-OOD IN TQB ASTIKIEB^ 

(Tiyaiologiral unatoaiydf tbe arteriea — Coiinw ofbliwd in thcartmSii — ^Elasiidtj 
of tho iLrtL-iivs— Conlracliljtj of t£jc arterieB — Ijocoiualiou. of thii art^riea and 
produrtioii of tho puise^Form of tlie pula« — Splij'ginogniph — Preeaure of 
blood in the antries^ — Dieiiinil3-D am u meter — Cardiometer — DLffLTiriLlittl tardi- 
OWeier— PrijasuFij indiBWenl parts of the arterial ayst«m — iDflucuceorrespi- 
radon no llie iirti'riut preeeur* — ElfutMa of hiuiuorrhngc — Rapidiij ut tho cur- 
renc of blood in tlui ut«rie4 — InstrumeDla for meuuring the npiiJit; of ib« 
ikrterial cin;iilfttloiL — ^Yarialioos in rapidity with the uclioD vf tb« heart — Ra- 
pidity in liilTLTeol pajU of tbe anerivJ aystuiu — Arterial murmuiG, . . 3-10 



onAPTER vn. 

OIBCTLATIO^ OF THE BLOOD US TBK CAPILLAIUES. 

Diatfnclloa b«tweea capiHurie* and ihe amnllesC arturica and v<dn« — Pbvsiotogival 
Aualoiuy of ihe capUliiTiH.'s — I'wulJariik* of distribiHioo — Capwity of the 
capilliiry aysl^m — Couivc of blood in the npiUdriei — Phenomena of the 
Capillary ciircululloD — Ruptdity of tlio capillary circulation — RelaUons of the 
iCBpUlory drculation to rcaplKnion— Catis-cii of the cdpUlar-y dreulurion— In- 
flnencA of tempenitore on lUo oipillary clrettlalioa — liiflurnco of direct irrita- 
tion on the capillary circulatioo^ ....... 278 



CnNTENTS. 11 

CHAPTER Vin. 

OIBOULATIOV OF THE BLOOD US THB TEDTO, 

Fhytiological aiuitom; of the Tons— Strmgth of the coats of the veiiiB— Talrcfl 
of the Teina — Course of the blood in the vdns — Pressure of blood is the 
Tana— Ri^iidit J of the Tenoos drcoUtioa — Cftuses of the renons drculation-T- 
bifiucnce of mnsculsr oontnction — ^Alr in the reins — Function of the ralre^— 
Tenous uiutomoses — Conditions which impede the tcuous drcolation — Re- 
gui^itont venous pal«e, , Page 801 

CHAPTER IS. 

FEOUUAsrnZB or THZ OZSOITLATIOK in DtFTZBENT PASTS OF THE BTSTEIL 

Circulation In the cnuual caritj — Circulation in erectile tissues— Derivative oircn- 
latioD — ^Pulmonary circulation — Qeneral rapidity of the cinmlation — ^Time ro- 
quired forihe passage through the heart of all the blood in the organism- 
Relations of the general rapidity of the circulation to the frequcDC? of the 
heart's action — ^Phenomena in the drcalatot; system afto: death, . . S8S 

CHAPTER X. 

BEfiPIRATION. 

General considerations—Physiological anatomy of the respiratory organs — Respi- 
ratory movements of the laryns — Epiglottis — Trachea and bronchial tube^— 
Parenchyma of the lungs — Carbonaceous matter in the lungs — Movements of 
respiration — Inspiration-^Musclcs of inspiration — Action of the diaphragm- 
Action of the Bcaleoi— Intercostal muscles — Levatores costarum — Auxiliary 
muscles of inspiration, 803 

CHAPTER XI. 

MOTEXBNTa OF XXPUUTIOIf. 

influence of the elastidty of the pulmonary structure and walls of the chest- 
Muscles of expiration — 'Internal intercostals — Infra-oostalea — Tiiangularis alert 
ni — Action of the abdommal muscles in expiration — Types of respiration-^ 
Abdominal type — Inferior costal type — Superior costal type — Frequency of the 
respiratory movements — Relations of inspiration and expiration to each other — 
The respiratory sounds — Coughing — Sneezing — Sighing — ^Yawning — Laugh- 
ing — Sobbiug — Hiccough — Capacity of the lungs and the quantity of air 
changed in the respiratory acts — Residual air — Reserve air — Tidal, or breathiog 
air — Complemental ur — Extreme breathing capacity — Relations in volume of 
the expired to the inspired air — Diffusion of air in the lungs, . . , 882 



12 CONTENTS. 

CHAPTER Xir. 

OHAKQES TTHIOH THB AIB TTNDBBaOSS m BK8PIBi.Tt(»r. 

Oenenl conddendoiu — Discoreiy of cubonio usd — I^acovery of oijgea — Con- 
position of the air — CoiuutoptioB of oxygen — ^InflneDce of tonperature — In- 
fluence of Bleep — ^Infinence of an increaaed proportion of oxygen in the atmos- 
phere — Temperature of the expired air — EzhaUtion of carbonic add— Influence 
of age— Influence of sex — Influence of digestion — Influence of (Uet — Influence 
of sleep — Influence of muscular actiritf— Influence of moisture and tem- 
perature— Influence of Beaaons — Relations between the quantity of oxygen 
consumed and the quantity of carbonic acid exhaled — ^Exhalation of watery 
vapor — Exhalation of ammonia — Exhalation of oi;ganic matter — Exhalatiou 
ofiutrogen, Page 400 

CHAPTER XIII. 

CaANGES OF THB BLOOD IN BSSPIBATIOIT. (IlctmatOtis.) 

Difference in color between arterial and venous blood — Comparison of the gases 
in renouB and arterial blood — Obserrations of Magnus — ^Analysis of the blood 
for gases — Relative quantities of oxygen and carbonic acid in venous and ar^ 
terial blood — Nitrogen of the blood — Condition of the gasee in the blood — 
Hectuuiism of the interchange of gases between the blood and the ur fai 
the lungs— General differences in the compo«tion of arterial and venous 
blood, 462 

CHAPTER xrV. 

BKLikTIOTra or BMPmAXIOK TO NCTRTnoS, KTO. 

TiewB of physiolf^ts anterior to the time of Lavoisier— Kelations of the con- 
sumption of oxygen to nutrition — Relations of the exi alation of carbonic add 
to nutrition — Essential processes of respiration— The reitpiratory sense, or 
want on the part of the sjstem which induces the respiratory movements — 
LooatioQ of the respiratory sense in the general system — Sense of euS'ocation 
— Reapiratory eflbrta before birth — Cutaneous respiration — Asphyxia, . 41% 



LIST OF ILLUSTRATIONS. 



nocits 

i. ADoetomDaing muscular fibres FrDin the human heart. (Kollicer.) 
2. Cardiograph. (Hxbkt.) ..... 

5. Sphygmograph. (Uaket.) ..... 
4. Trace of the pulse, after Viorordt. (Hahet.) 

6. Trace of the pulse, after Harey. (Uakeit.) . 

6. Unmadynamometer. (B^clabs.) 

7. Cardiometer. (Birnabd.) ..... 
6. CompensatJag hamometer. (Uaret.) . 
9. InBtrument for measuring the rapidity of the flow of blood in the 

arteries. (CuiurvAti.) ..... 

10. Hould of a terminal bronchus and group of air-cells. (Robih.) 

11. Diagram of the action of the riba in inspiration. (Sibson.) . 

12. Idem 

13. Idem. ....... 

14. Idem. ....... 



181 
198 
2S8 
20ft 
257 
2fi2 
263 
2U 

273 
S6S 
875 
875 
S75 
875 



PHYSIOLOGY OF MAN. 



mTEODUCTION. 

Oenenl cotuideratioDB — Phyaiologictl properties of organized stnictnres — Prozi- 
mate principles — Inorganic princlplee — Organic non-nitrogenized principles 
—Organic nitn^enized principles. 

The epoch of purely speculative reasoning, without the 
basis of established facts sufficient to justify any connected 
theories, belongs to the remote history of Natural Science. 
The ideas of the great philosophers of ancient times, who 
studied Nature by what may be called the intuitive method, 
have been gradually giving place to doctrines based on the 
observation and investigation of phenomena. Ages of ob- 
servation and generalization of facts by the greatest intel- 
lects have pat us but little beyond the threshold of the 
great domain of Science. But we have learned enough to 
know that all Nature is regulated by immutable laws. Stu- 
dents of her phenomena should be more than content if per- 
mitted to discover some of the truths, the development of 
which marks the scientific advancement of each succeeding 
age, though they may seein an insignificant portion of what 
is to be learned. It is only by accurate observation and 
generalization of a sufficient number of phenomena, that 

the laws of Nature are to be discovered. They are a part 
2 



H 



ciTBOpircnoK, 



of ftn infiiiito and liarmomouiS eyetem. We canJiot liope to 
arrive at a Unowled^e of them bj pure reasoning ; or by 
asfuniin"^ tlirtt tliey aro in accordant'e with definite principleg, 
tiio oftou tlie ofl'siiring of our o^m limited iutelleetB. Jsever- 
theless, it is a phystcilogical attribute of the liuman mind to 
desire to press on in advance of oliscrration, and to form 
theories, wLicli may or may not l>e carried out "by the suc- 
ceeding development of aetual knowledge^ Tbeoriea wliicb 
are tiot built upon lalse or imperfectly observed pbenomena, 
are the pioneers of actual discovery, Wlien theoretical pre- 
conceptione are justitied and corrected by original observa- 
tions and experiments, with the brain to conceive and the 
will to execute, man, in thus working out the great problems 
of Ivature, is i'liliilling' one of the highest purposes of bia 
usisteiice^ 

With the few facts which irere at first known, the 
ancient speculative philosophy proteased to embrace the 
whole of natural science; but as discoveries were made in 
different departments, a di^-iaion of labor became necesMrv. 
"We uow find ditiferent clashes of scientific men, each working 
in a particular sphere ; M in tbe lower zoological divisions, 
a single organ pertorms all the varied iiinctiotiB of nutrition, 
wliile ill the higher ordersj when the processes of life are 
more intricate and complicated^ the ejstem ia divided np 
into ohiboiiitely -organized parte, each of which has an allotted 
office. 

From the time of Galeu may l>e eaid to date:, aa distinct 
from ostrononiy, chenii&try (or rather alchemy), physics, Ac., 
the ficieoce which is now called PmisioLoor. 

PhyaoI<^\ from its etymology^ signities the Bcience of 
Kaiore ; but in the setifie in which the term is, now n^ed, it 
may be defined to be tAa tcifnc^ qf /» A More elaborate defi- 
tutious have bees given, bnt they only qualify and explain the 
meaiucig of what we know as life. 

A natur&l division of pbysiolug;)' is into AnitUA] and 
vegetable; and again, into the phraiology of the infezior 



OESEttAI. CO'fllPERATlONB. 



15 



ttnimals as compared witli man, or comparative phygtology, 
and the Physiology of Man. The latter^ wliidi is Uie anb' 
ject of the preseot work, is jteculiarlj mtereeting to the 
physician,, as the basis of all accurate knowledge of the 
science of medicine. 

In the early history of phyaiologioal science, the develop- 
ment of anatomy necessarily gave na mnch information con- 
cemiiig tho functJona of the body ; and we now Iiave to 
actnowledge qui continual indebtednees to aaatomieal inves- 
tigfttions, particularly those made with the aid of the imcro* 
scope, foriuiportaot advaucemeDta iaphj-siology. In treating 
of the subject, it is impoBeible to negleut what is most appro- 
priately called the phjsivloytcal anatomy of parts, a knowl- 
edge of which alone enablea us, oftentimes, to comprehend 
their functions. For example, we can scarcely conceive how 
the anatomy of the circulatorr eyatem could he clearly uuder- 
Btood without giving us a knowledge of its physiology. 

Chemistry, also, when the components of the body arfl 
Btadied in such a way as not to destroy their properties as 
organic coiiipontids, has a most important hearing on the 
advimcement of physiology, Aa a striking; example of this, 
we may take the discovery uf the properties of the gasea of 
the air and their relatione to the blood by Lavoisier, which 
gave us the first definite ideas regarding the eesential phe- 
nomena of reapiration. "We are now largely indebted to 
moA&n\ j^f'lC^^olotjical chemistry for a knowledge of many of 
the essential phenomena of lifa, and look to a farther develop- 
ment of thia science for an elucidation of many important, 
but stil! obscure, fjuestions eounectcd with nutrition, 

Cert-ain physiological fiinctions arc in exact accordance 
with established physical laws; which are competent, for 
exmnplo, to explain the refraction in the Btructurcs of the 
eye, or the conductioa of vibrations in the ew. Physical 
laws are involved in most of the phenomena of life, but are 
generally more or less modified by the peculiar properties of 
organized bodies. 



16 



nsTBODccnox. 



31any of the phenomena of life are made clear by a 
comparison of the physiology of man with that of the infe- 
rior animals, which is oflen eimpler aiid more easCy itivesti- 
gftted. 

Ab phyBioIogy is the natnral and only correct basis of 
pathology, we frequently derive important information &i 
to the fpttctions of parts by etudying the effects of disease, 
by which their functions are modified or abolished. The 
experiments thug perlbrmed by IlT^ature On the htinian. aystem 
are frequentiy more instructive than those which we make 
on the inferior animale. 

As the complement to anatomy, human and comjiarative, 
organic cliemietry, and pathologjy, we have afl the most pre- 
cious and fruitful means of physiological investigation, direct 
ob^rvation of the phenomena of lite in man and the inferior 
aninialfl, and experiments on animals by vivisection b. The 
present condition of physiology Us a testimony of the incal- 
culable yalue of this method of study. Were it consistent 
with our plan to follow out the general development of the 
science from an historical point of view, we should tind tho 
names of Harvey, Asellt, flaller, Jlales, Spallanzani, Ed- 
wards, Bicbat, Bell, Magendie, and a Lost of others, bearing 
witness by their ii'orks to the value of vivi&ectiona in phjuio- 
logical investigations; to say nothing of the great obsen-erH 
of tho present day, who are constantly adding to our knowl- 
edge. The tield would he sterile indeed were it not for 
ex|>eriinents on hving animals; and the loss to the science 
which has for its object the alleviation of the saffering* of 
mankind, would have been incalculable, had phy&iologists 
been unwilliug, from false motives of humanity, to indict 
pain upon the lower animals, which is to a certain extent 
unavoidable in experimentation. 

Fhyeiologicttl litLTature, in the great KlemerUa PhysiolO' 
ffim of Holler, which l>elottged to a past generation, and 
the elaborate systeraatic works of Bcrard,' Longet, Miiller, 

' Bimrd did ncyt live to coca|;t1«le Ida groil vtnk <m phfiiology. E« dieU 



G£:SXBAI. C0:SSID'ERAnOS8. 



IT 



and other experiineutaliata of the present generation, fiir- 
niabes abTrnJact proof that tlio fiieulty of observation imd tlie 
power of generalization are not uecesaarilj' inconBiiitent with 
Cftcli otiier. 

It would be futile to attempt to point out flll the difHcul- 
tiea and fiouroes of error in experitnentationon living aninjals. 
These must be overTOme by the physiologist after he has 
become practically acquainted with tliera. It mast be borne 
in mind, however, that we aa-o interrogating Nature ; and 
onr sole aim mnst be to pat our questions intelligently and 
interpret the answers eovrectly. She does not nnfbld her 
mysteries to the careless and inconsiderate olraorver. An 
accident may lead the reflecting student to tmnie a piu*ticular 
Bet of experiments, for the explanation of an unexpected 
phenomenon ; but we ahoidd go to work with an idea of what 
we wish to know, always ready to correct or abandon our 
roo&t cherlsbe<:l preconceived notions if we find they are not 
Id accordance with facts. Experiments shonld not bo isolat- 
ed. A golden opportunity is thrown away if we stop abort 
of the end in a legitimate series of investBgationa; for none 
are better fitted to go through the later steps of a natural 
ecTies of experiments than they who have conceived and 
executed the first. 

With the many varying conditions of the system which 
ineTitflbty occur in living animals, it is almost nnnotcsaaty* to 
add that an important observation should be repeatedly con- 
firmed, and the answer to our experimental inquiries obtained} 
if possible, in different ways. It must be remembered that 
KatUTQ never contradicts herself, and has no exceptions. 
Her laws are invariiilile ; and if expenmcnt& be apparently 
contradictory, we must look for differences in the conditionB 



rhorllr after he haJ oommencud the publicn'tiou of the fourth volume iu ISnA. 
Jhc proffffomhifi, ud the Bcctions on digestiQii, absorption, ilic blood, rettipira- 
tion, ani.I circnIatiOD, are pcrbnpu the nio^t i^dDdid, CibniiBliTL', fttid bfflt con- 
sidpred i>««ii}'» ou tlieae Bctbjecta in aoj language, parucularlj' in Ibe waj ot 
bibliograpiiiciil research. 



IS 



raTBODrOTIOH. 



under wliich tho observntioDB were made. It would be 
always possible lo reconcile dlseordiiut rL'snltsof oLservatioits, 
were we able to entiroly appreciate the contlitiana nndci 
which they were made. For this reason, a practical physiolo- 
gist, if entirely unbiassed, is most competent to judge of, and 
aa&imilate, the obeeri'ations of otliere. 

Vital Properties of Organized StrtcHures. — In com- 
mencing the Btiidy of pliysiology, we should have some idea 
of the phyeiolo^cal chemistry of the body, comprehending 
folly^ in the first plate, what is meant l>y life, or the vital 
properties of tlie tisauefi. 

The tissote ■wliich are endowed with vitality are in a 
Btate of continual nietamorphoeia, more or leas active accord- 
ing to their degree of organization. They are eony.tantly 
nudei^ing tranaforraation into what are known as effete 
raattere and have the property of appropriating, in the great 
majority of instanced from the blood,, inaterinl for tlieir re- 
generation. In other worda, under proper conditions, living 
tiBsiiee have tho property of self-regeneration. Thie constant 
waste, or phy&ioloon'cfil disintegration, ia known nnder the 
name of disassimiLition, and its products are called excre- 
tions. The power of eelf-regcnci'ation is called nntntion. 

This projwrty aftects all tho coiistitneuts of the body 
without esception. We shall see that physiological cheniie- 
try divides the conetitnenta of the organism into organic 
and inorganic principles; the lat(«r being identical with 
principles found in the inorganic woi'ld. Inorganic prin- 
ciples, in the living body, are always in union with organic 
principles; they are regT.tIarly thrown oft' with the products 
of their dieaseioulatioD, and are Btipplied to all the tisguea as 
a necessity of nutrition. They never exist in their crystal- 
line form, in which they so tximmonly occur in the inorgaoic 
kingdom.' Every part of the body either ie, or has been, 

' There ii a single «iccpti(>n 16 IhUi Uw in the crTsUla of cirbODAte of Um« 
trhlcfa kre fouttd in the intenial etr, coDstitntuig the otoconia or ouUtha. 



THE PHOPEETnca OF OEOASTZED STKrCTTEES. 



19 



endowed witli life. Some are desqiiftmatetl and reproduced, 
like the nails, hair, or epidermis; some are worn away and 
not reproduceil, like tEie ennrael of the teetU ; but tliey are 
all sabjeet to vital laws iu their formation, and the esceptiona 
to tUo Saw that each tissue haa the property of aelf-regenerft- 
tion are very few. 

Tiie power of ftelf-regeneration of organized tisanea oan- 
not exist itidetiiiltdy. After a time the tissues fail to appro- 
priate encjcgh orgiiuic matter to entirely supply the waste; 
they gradually degenerate, and finally die, as a necsaary 
conditioo of their existence. The activity of the regenorat- , 
ing powers eeeins to depend on the projx>rtiou of organie 
matter which the tissues coutaiu. In childhood, when, as » 
condition of growth, the nutrition ia greater than the waete, 
the organic matter of the tiaaiiea is En excess. In old age 
calcareous deposits are tre<]nent, and the inorganic matter 
in til parts is in excess, until finally the organs become incar 
pnble of performing their functions, 

Tho properties ahote mentioned serve to distingiitsh 
orgauized living bodie& irom those not endowed with hfe, 
Man, in the general properties of lus tisAuea and organs, 
does not differ froiri the lugher classes of the inferior animals, 
Hi the mammalia. Their tissues are as highly organized, 
and the various functions connected with nutrition, sucli as 
secretion, digestion, circulatiun, respiration, etc., are epsen- 
ttally the same. In some instances, as In the digestive time- 
tion of some of the herhirora, tlie process ia even more 
elaborate than in the human subject. For this refison, 
with proper precautions^ we can apply without hesitation 
mo&t experiments on the mammalia to the physiology of 
mnn. 

To the development of the great centre of tlie nervous 
Bystem, man owes his preiiniineiiee in the animal scale. In 
the words of Longcit: "In hia psychicul relations, but in 
these only, man can constitute a distinct kiugtiom, Physt; 
ology has specially in view the acts which asBlmilate man to 



un'EOPPcnojJ. 

aninials ; it belongs to peycliologj to itudj? and make known 
tlie faculties ^vbich separate liim from tLem." ' 

Even iv'ithont accidents, pbyfiiologtcal death is a neceesity 
of existeuce ; but Nature has provided, as. one of the most bii- 
portant attributes of organization, a means, by wbicli oi^an- 
ized bodies may be perpetuated tbrough all ages. In the fully- 
devoloppd organism are produced two kinds of organic ele- 
tuentSf the uiale aud the leiuale. These, when brought in 
contact with eacL otlier under proper eouditions, arc capable 
of being developed into a new being, Bimilai In organization 
to, and designed to take the ploec of, tlie one wliidi is to paba 
away. These new beingB are generated in Bufficieut number 
to insure the perpetuation uf the species. 

The excrementitious products of the body during life, and 
the body itself after death, changed by the peculiar proceea 
of putrefaction, are returned to die earth aud to the air, and 
contribute to tlie nutrition of the vegetable kingdom. The 
vegetables, in their turn, ai-e consumed iu the nutrition of 
aniniale. All the elements necessary to nutrition, except 
oxygen, are taken into the alimeutary caiial a& food. Our 
food consists, either of vegetahlts, or the flesh of animals that 
are nourished by vegetables. 



PBOSmATfi ^EXSCtFLM. 



From the preceding general remarks, it ia evident that 
physiology, to be systematically and properly Btudiedj must 
be connected with physiological anatomy and chemistry* 
The physiological anatomy of special organs and Eystema 
naturally precedes tho consideration of their fimetions ; and in 
treating of the functions of other parts, more especially the 
nutritive and excrementitious fluids and the aecretions, -wo 
(ue unavoidably led to consider fully their chemical constitu- 
tion. There are, however, certain coastituents of the body, 

' LONOffr, Train de P\\/(iolo^t, Vant, IBAS, tome L, p. xnvii. 



PBOXDUTE PRINOIPLBB. SI 

a fall consideration of which, in connection with special 
functions, would be out of place, as well as many points in 
phjfiiological chemistiy, showing the relations of the dififerent 
elements to nutrition, etc, ; hence is desirable, as an intro- 
duction to physiology proper, a brief review of the prox- 
imate principles of the economy. In this introduction it is 
not proposed to treat exhaustively of physiological chemistry. 
Such principles as will demand, from their connection with 
special functions, extended consideration in another place^ 
are omitted or simply alluded to, as well as some which have 
a very unimportant or obscure function. 

If we were to study the constitution of the body from a 
purely chemical point of view, it would be divided into 
elementary substances, or those which are absolutely incapa- 
ble of further subdivision. In this way we should lose all 
distinction between organic matters and those which enter 
indifferently into the composition of all bodies in Nature, 
whether inert or endowed witli vital properties. After 
having thus ascertained the ultimate constitution of the 
organism, we have learned all that is possible by this method ; 
for we are already familiar with the properties and be- 
ha^-ior of elementary matter, as obtained from the inorganic 
kingdom. 

In physiological chemistry this method is inadmissible. 
The substances which are presented for our study in the liv- 
ing organism are endowed with peculiar properties. Their 
ultimate composition is of little consequence compared with 
a knowledge of the laws which regulate their behavior, not 
as elements, but as constituents of an elaborate animal or- 
ganization. 

We can separate from the organism of animals substances 
of a peculiar nature which are never found in the inorganic 
world. These demand our special consideration. If we 
attempt to study them by the ordinary chemical processes 
of analysis, they are destroyed and lose their properties as 
organic principles. 



S2 



rNTHODDcnoir, 



Combined -with tliese orgiinic principles we alwnjg have 
a certain projxirtic'U of inorganic ntattei-s wbich iiiny, it ia 
true, lie separated I'mm tbem eiisilj, and apparent!}- withont 
decomposition, but "which are, notwithstanding, necessary to 
the peculiar properties Iiy which we recognize organic sob- 
BtanceR. Their phTsioIogical union ia b-o intimate that they 
may justly be considered as organic, though originating in 
the inorganic kingdom, 

Chemistry recognizes about seventy elementary siib- 
Btancee, of is-hicb eighteen or twenty enter into the consritu- 
tion of the human body ; but as pliyeiologiste, wc must make 
a division of the body into component principles, without 
reference to the eleujentary subetances themselves, but with 
a view to the form and condition of their existence in the 
organism. Aa we have seen tliat the distinguishing properties 
of organic p'rinciplea are destroyed when they are reduced to 
their ultimate elements, it is evident that many or most of 
the principles into which the body is divided physiologically 
are compound subfitances. 

From this point of view, the organism may he said to be 
com|JO&eJ vi' Immediutu or I*roxitn<ite I^rhicijf/es. 

A ProxiTnat^ J^rinciple may be defined to be a guhstance 
Kutraiicd from the hori//, wh tch cannot he fnrHier suhdiviried 
mlihout chetnical (iecomj)o»iti(/n and lose of its charaetaristic 
pTOjteTti.es. 

According to Robm and Terdeil, there esist front eighty- 
five to ninety distinct proximate principles in the human 
body.' 

Tlie distlQction between proximate prindplca and chem- 
ical elements i& apparent from the definition above given. 
To tllustrate tlits difference, however, we may take the fol- 
lowing example?. Chloride of Bodium in an important proxi- 
mate principle, and is composed of the uhemical elemenla 
chlorine and sodium. As chloride of sodium, it Una certain 

' Robin and Tebszil, (JhimU Anaiiymi^ ri Fhynvlo^qutt Parity 160^ 
lomo L, p. 136, 



FBOZSATE PEtXCTPLES, 



S3 



properties, and is eudoTred with certain functions in theepon- 
oii^jTi wliif!i are, of coiiree, entirely different from the proper- 
tit's of chlorine or sodium ; the latter especially being only 
ohtnined in a state of chemical purity hy a difficult and elab- 
orate process of manipulation. As phTgiologists ^'e have 
nothing to do with the pro\>ertie8 of chloriHe, or the rare 
Caetnl sodium ; wc only wish to know aa much as pogsthle 
about the functions of thuae two bodies united to forai com- 
mon sitlt. Ag^ain, tihrin, a proximate principle luunci in the 
blood, may bo rediiced bj chemical manipulations to a cer- 
tain nnmijer of atoms of carbon, hydrogen, oxygen^ nitrogen, 
and sulphur. Bnt a knowledge of even the esact proportions 
of these ingredients would be of no practical benefit, if we 
were unfioquainted with the general properties of fibrin and 
its ttses in the economy. Salt cannot be subdivided into 
chlorine aitd sodium, nor fibrin iuto its eleinente, without 
chemical decomjioaiiion and losa of characteristia proper- 
ties ; but both of these substances cnn be extracted from the 
body in the condition in which they exist in the organiam, 
and tire therefore proximate priuciplea. 

A constituent of the body niny be at the same time a 
chemical element and a pmsimnte priuL-ipIe. An exuniple 
of this ia the free oxygen in Bolntion in tlie blood. This 
enjoya, in the body, the properties of free oxygen, and may 
be extracted from tlie blood by mere displaccmetit with an- 
other gas, or by the air-purap ; a process quite different from 
the elaborate chemical manipulation wliicli would be necte- 
ear}' to obtain oxygen by decompoaition of tibrin, albumen, 
or any compound principle. 

The principlcjs which compose the body, with the excep- 
tion uf excrementitions Bubstancea, exi&t in onr food; tliis 
being the only way in which material is supplied for the con- 
tinual repair which ia characteristic of living tiasuea. They 
are vCA introduced trom without. Certain principles^ such a& 
Water and the inorganic salts, are merely transitory in the in- 
terior of the body, and are discharged in the same form in 



94 



■which they enter. Others are coceumed in the pi^ocess of 
repair, and after having performed their futictione, are thru'wn 
off as eff'eie loatterB. Examples of the latter are tiljrin 
and albatnen, which are tranaformed flret into the snh- 
stance of the tissues, and then into area, creatine, choleste- 
rine, and other exereinentitious matters, wbieh are the re- 
Bolt of the hreaking down or sewing out of the tissues. 
Finally, there are eertain principles, the sngars and fata for 
estaiiiple, which have an important connection "itli the pro- 
cess of nutrition, and disappear in the eygtem ; but their 
traasformatione we hare not m yet been iil»le to follow,, 
These, hesides being taken in as food, are manufactured hy 
certain organs, and appear lie novo in the economy. 



Division of I^roaimate Prindjpl^s.^-lfi the division ot 
proximate prindplea, we shall follow, with slight modifica- 
tionSj the tlassificjition of Robin and Ver<3eiL With refer- 
ence solely to anatomical and physiologii-'fll chemistry, the 
classification of Ibeee autliors cannot be improved; hat in 
treating of the whole euhject of physiology, it will be conven- 
ient to take up certain of the elemente in ccnneetion with the 
functions in which thcj play an important part. Oxygen 
and carbonic acid, for example, will he fully eonaidered in 
connetilion with respiration ; urea aud choleatertne with ex- 
cretion, &c A^ain, there are some, having funcliona appa- 
rentlv of so little importnnce, or bo obBcore, that, while they 
may be interesting in a chemical point of view, merely iis 
constituents of the body, it is not worth while to treat of 
them in connection with phyaiology. 

The two great divisioni of proximate principles which we 
propose, comprise : 

FiBST, Suhdancee W*mA tnt^^r into the nonmtl rtm- 
giUutum qf the organUed iiMuts, anil iho»» ootutitutnls iff 
thejittids which are tund in nutrition* 



PBOXIMATE PEDfCIPLES. 



25 



Seoosb. Su7)Stai\cm which are the rentilt of ifte toeitring 
out of the tuvmSf and are not m&2 in nutritloiC 

The first dirision, which ia tbe only one that wiU be taken 
up in this connection, may be eiibJivided, according to the 
claasificatioD of Robin and Verdeil, into three classes. 

1. Inorganic St^stancfs, — This class ia of inorganic ori- 
gin, definite chemical composition, and cryetalliiable, Th« 
substances forming it nre all introduced from Tvithout, and are 
all discbarfced Irom the body in tbe same form in whicli they 
entered. Tbej never exist alone, but are always coiribined 
with the organic principles, to form the oi^anized fluids or 
solids. Tills union is " atom to atom," and ao intimate that 
they are taken np with the organic elements, aa tbe latter are 
worn out and become effete, and are discharged from the 
body, thongh theraselveB unchanged. To supply the place 
of the principles tlras thrown oiF, a fresh quantity ie depos- 
ited in the proce&s of nutntion. They give to the varions 
organs important properties ; and, though identical with a;ib- 
Btances in the inorganic world, in tbe interior of the body 
they behave as organic substances. They require no special 
preparation for absorption, but are soluble and taken in un- 
changed. They are received into the body in about the same 
proportion at all periods of life, but their discharge is nota- 
bly diminished in old age ; giving rise to calcareous incrusta- 
tions and deposits and a considerable increase in the calca- 
reons matter entering into the composition of the tissues. 
Afi e-^nraples of this class we may cite water, chloride of so- 
dium, the carbonates, etilpUates, phosphates, and other inor- 
ganic Baits. 

2. OrganiQ Non-Nitro<jenized Siibsiances. — This class oi 

' Tliiq (iiriglon \s ccmpoecd of f£<.Toa)i.iitiiiou& mattera, wliich will b? fu]]> 
eonmdcivj wbuti mating of excretion. It \i iududed in tbe £«&□<] dasa of proc 
bnate principlt-a b; HoLiii nod TcrddL 



96 



ISTBODrCnOH. 



proximate priaciples is of organic origin, delioite chemical 
compc^ticD, and crysfallizalile. Willi the exception of tbe 
B&lts peenliar to tlie bile^ wliicU "witl be con&idereJ "when we 
come to tn-ni of that fluid, piieumie acid, and one or two 
nnimportant principles, tbey are distingniahed by being com- 
posed of tbree el&menta, CaTbon^ Hjdrogen, and Oxygen, 
As they thus contain bydro^en add carbon, to tbe exeln^ioB 
of all other elements, except the almost aniTer^al priDCtple, 
oxjgen, tbey are freqnently epofcen of as Hydro-earbofxt. 
They are distinguisbed from other organic gnbetanccE by the 
absence of nitrogen, which has given thom the name of Xf/n- 
nitrogenJ.2^d or JVon-asottsed snbstancea. They are intro- 
dnced into the body as food, and are mannfaetnred in the 
economy by speeial organs ; but, nulike principles of the first 
daas, with the exception of su^ar and fat, which are dis- 
charged in the intlk daring lactation, are nefer discharged 
from the body la health. The principles of this class play 
an important part in developinent and nutrition. One of 
tliem, s^igar, apj^ears very early in foetal life, formed first by 
the placenta, and afterward by the liver ; ita Ibrmatlon by 
the latter ot^an continuing during life. Fat is a necessary 
element of food, and is also formed in the interior of tlie 
body. The exact influence which these Bub^tauces have oo 
derelopment and nutrition ia. not kno\m, bnt experiments 
tmd observation hare shown that this influence is important. 
Hany physiologista are of the opinion that principles of this 
c!as6 undergo direct oxidation or fombuBtion in the Inngs, and 
lia^e the exclusive office of keeping up the animal tempera^ 
tnre. At one time, indeed, they were generally sj^okf-n of as 
calorific elements ; hut in the present ctfuditiou uf science tliis 
exclusive view i» not tenable; and we ehall &ee, when treating 
of the subject of animal heat, that its production cannot be 
referred entirely to combustion of tlie hydro-carbons. The 
gugaiB and fates, lactic acid and tlie lactates, pneumic acid and 
the ^menmatc!?, the futty acitU and their combinations, conati* 
tnte the most important pnuctples of this claaa. 



PKUilUATE PBraCTPLtia. 



27 



S* Orguni-G Kitrogpniserl Suljfitdncen. — Tliis class of prox- 
imate printiLpIes is of orgtinEc origin, indefinite clieniiwil com' 
position, and non-crjatnllizable. Substances forming; thia 
class are Apparently the only principles which are endowed 
with Wtal properties, taking rftaterials for their regeneration 
from the nntritive fluids, and appropriating them to form 
part of their own Bnlistaiice. Considered from this point 
of Wew, thej are different from any thing which is met with 
ont of the living body. They are all^ in the body^ in a state 
of continual claange, weai'ing ont and becoming effete, when 
they are transformed uito escrementitioua Bubstancos, which 
constitute the setond grand division of proximate principles. 
The process of repair in tLls instance is not the same as in 
morganic sabstances, which enter and aie discharged from 
. the body without undergoing any change. The analogous 
Bubetances which exist in food undergo a very elaborate prep- 
aration, by digeatioQ, before tliey can even be absorbed by 
the blood-vessels; and etill another uhanga talvea place 
when they are appropriated hy the various tissues. They 
ejdst in all the solids, semiBolids^ and fluids of the body, 
never alone, hut always coinbined with inorganic suhstances. 
As a peculiarity of clicmical constitution, they all contain 
nitrogen, which has given them the name uf I^iiroyenised or 
Asottsed principles. As before intimated, they give to the 
tiaaues and fluids their vital properties. In studying their 
propertica more fully, we shall 6ce that they are by far the 
most important elements in the organism. The elabonite 
preparation which they require for alworption involves the 
most important part of the fnnetioti of digestion. Tiieir ab- 
solute integrity 13 necessary to the operation of the essential 
functions of many tissues, as muBcnlar contraction, or con- 
duction of nervous force. An exact knowledge of all the 
transformations which take place in their regeueiation and the 
process by which they are converted into effete or exeremen- 
titious matters, would enable ua to comprehend nutrition,, 
whieli is the essence of physiology ; hut aa yet we know little 



28 INTKODDCnON. 

of these changes, and consider ourselves fortunate in nndcr- 
Btanding a few of the laws which r^ulate them. As exam- 
ples of principles of this class we maj cite muscnline, os- 
teinO} fibrin, albumen, and caselne. 



mOBQANIO FBIN0IPLE8. 

The number of principles of this class, now well eetab- 
lished as existing in the human body, is twenty-one.' All 
substances which at any time exist in the body are proximate 
principles ; but some are foimd in small quantities, are not 
always present, and apparently have no very important fnac- 
tion. These will be passed over rapidly, as well as those 
which are so intimately connected with some important fimo- 
tion as to render their full consideration in connection with 
that function indispensable.. The following is a list of the 
inorganic principles, excluding those which are excrementi- 
tious, and one or two which are not yet well established : 

2'abie of Inorgcmio Ji^rinoi^les, 

ProKimaU PHneipl*. Whert Found. 

Oxygen. Longs and Blood. 

U;dr(^en. Gases of Stomach and Colon. 

Niteogea. Lungs, Intestinal Oases, and Blooi 

Cuburetted Hydrogen. Lungs (expired air], Intestines. 

Sulphuretted Hydrogen. Lungs (expired air), Intestines. 

Water, TJnirersaL 

Chloride of Sodium. Universal, except the enamel. 

Chloride of Fotusium. Uusclee, Liver, Hilk, Chyle, Blood, Hu* 

cus, Saliva, Bile, Gastric Juice, Ce- 
phalo-rachidian Fluid, and Urine. 



* Rotun and Verdeil give tventy^oine ; but of these, three (acid phosphate of 
■oda, acid phosphate of lime, and ammonio-magneeiaD phosphate) are found only 
IB the urine, and may be considered as coming under the bead of excrements, 
with carbonic acid, which is one of the most important excretions ; one (bicar- 
bonate of lime) is abnormal ; one (bicarbonate of potaaaa) is found only in cer- 
tain of the inferior animals ; and two (carbonate and bicarbonate of ammoDia) 
are doubtful. 



INOBGAHIO PBmCIPlES. — QASES. 29 

JhvHmaU Frinetpltk Wktre Found. 

Phoepbate of L\m.-. (basic). UnlversaL 

Cubooate of TJiat. Bones, Teeth, Cartilage, iDternal Ear, 

Blood, Sebaceous Hatter, and eorno 

times Urine. 
Caibooate of Soda. Blood, Bone, Saliva, Ljmph, Cepliolo- 

ractudian Fluid, and Ctiii& 
Carbonate of Potassa. Blood, Bone, Ljmpb, and Urine, 

Phoepbate of Uogneaia. Universal. 

Phosphate of Soda (neutral). Universal 

Phoepbate of Potassa. Universal. 

Sulphate of Soda. Univctsal, except lUlIc, Bile, and Ga.*tTio 

Juice. 
Sulphate of Potassa. Same as Sulphate of Sods. 

Sulphate of Lime. Blood and Feces. 

Hydrochlorate of Ammonia. Gastric Juice, Saliva, Tears, and Urine. 

Carbonate of Magnesia, A trace in the Blood and Sebaceoni 

matter. 
Bicarbonate of Soda. Blood (Liebig). 

The Oases. 

The gases (oxygen, liydrogen, nitrogen, carboretted hy- 
drogen, Biilphnretted hydrogen) ' exist both in a gaseous state, 
and in solution in some of the fluids of the body. Oxygen 
plays a most important part in the function of respiration ; 
but the oflBce of the others is by no means bo essential. Ni- 
trogen seems to be formed by the system in small quantity, is 
taken up by the blood and exhaled by the lungs ; except dur- 
ing inanition, when tlie blood absorbs a little firom the in- 
spired air. It exists in greatest qaantity in the intestinal 
canal. The carburetted and sulphuretted hydrogen, with 
pure hydr(^en, are found in minute quantities in the expired 
air, and are also found in a gaseous state in the alimentary 
canal. From the offensivei nature of the contents of the 
large intestine, we should suspect the presence of sulphuretted 
hydrogen in considerable quantity ; but actual analysis has 
shown that the gas contained in the stomach and intestines, 

' Carbonic acid is bote omitted, and will be treated of under the bead of re» 
piration. 



so 



DrTEODTCTIOS;. 



luge as well aa small, is compaeed chiefly of nitrogen, with 
hydrogen and carbnretted hydrogen in about equal propor- 
tion, five to eleven parts per hundred, and but a trace of sul- 
phuretted hydrogen. ^Ith the exceptioD then of oxygen 
tjxd <;arbo&io acid, the latter being on eicretiou, the gases do 
not bold an important place among the prositnate principles. 
At all events, their functioo, whether it be important or not, 
is bat little ander&tood. 



Water. 

Water l& by far the most important of the inorganic prin- 
dples.' It is present at all periods of life, existing even in 
the ovum. It exists in all parts of the body ; in the fluids, 
fiume of whieh^ as the lachrymal fluid and perspiration^ con- 
tain little else, and in the hardest structurea, as the bonee, or 
the enamel of the teeth. 

In the solids and semisolids it does not exist as water, 
but enlera into their structure, assaming the ooD&ie>t«nce 
by which they are cbarai-terized. For example, we have 
wat^r in the bonee>, teeth, and even in the enamel, not cou- 
taitied in the interstit-ej of their strmture, u in a sponge^ 
bnt incorporated into the «ul>»tarice of the tiaeae;. In these 
Htuations it i& essentially it<ti^rqf comjioeilion. Daring the 
procees of natritioi, water k deposited in the tiaeues with the 
other nutritive principles, as we have it incorporated in the 
snhetance of certain inorganic componnik in the proceaa of 
crystallization, when it is known in chemiatiy as wat^r (^ 
cT^ttallUation. In the interior of the body, water ia thoa 
incorikorated in the snbstance of organic mailers^ trAiVA arv 

* iBCOi^tiagprtBciptM'irhiiAi wwuM lBlrttoMdlaMvaiim- 
pmibl t IP ny tto «» to ab tc l aMy men hipartwl iImhi MMhw; iMU, vritan 

»^ia of ihft tmAj, fAwflj rtth raftwea ■> fMx HMrtJiy mA iht «iMMa(tMr 
iliMributloa. WWn w* con* W MfHde pfariplM, we AtH m« Out iha« «» 
iwulwttv (be moil LapoTUni ooulibiMttt of Iha Ii«iK( inoij, w K**^'¥ to tht 



WATER. 81 

<^ iTidejin'Ue chemical composition^ and non-crystdUisabUf 
and we have no reason to be surprised, as physiologists, to 
find it entering into their composition in incUfinite propor- 
UonSj assuming the form and consistence of the organic aidh 
stance. Our definition of a proximate principle is: "a sub- 
stance extracted from the body, which cannot be farther 
Bubdivided without chemical decomposition." The union 
of water with the oi^anic principles is chemical ; and though 
feeble, is not more so than the chemical union of elements 
in acme compounds found in the inorganic world. The bi- 
carbonates, for example, are formed by a union of two equiv- 
alents of carbonic acid with one of the base ; but the second 
atom of carbonic acid is in so feeble a condition of union, that 
it is set free when the compound is placed under the receiver 
of an air-pump. It might be objected that water is combined 
with organic substances in an indefinite quantity, while the 
carbonic acid is present in definite proportion ; but it must be 
remembered that indefinite proportious of all the constituents 
are characteristic of organic substances ; and that the quantity 
of water existing, within certain limits, in indefinite propor- 
tions, only obeys the law which r^ulates the components 
which are universally recognized as existing in a state of 
chemical union. The only difierence between water and the 
other constituents of an organic compouud, is that the former 
is extracted with facility ; as one atom of carbouic acid is 
extracted from the bicarbonates more easily than the other. 
Studying the organism as physiologists, we must consider 
water as an integral constituent of the tissues, and not as 
merely absorbed by them. 

AH the organized structures contain a certain proportion of 
water, and this is necessary to the performance of all or any of 
their fxmctions. If a normal muscle be considered as a con- 
tractiug oigan, and a nerve as a conducting organ, or albu- 
men as a nutritious element, we must consider, as one of their 
wnstituenta, water. It is necessary to the proper form, consist- 
ence, and Amotion of these and all organized structures. In 
analysis of organic matters, wheu water ia lost or driven off 



32 



cirrBODCcnoiv. 



in our manipulations, tlie principle is not brou^bt near a state 
of cbemiciLl purity, but is essentially and radicallv changed. 

The quant it ij of itiaf^ t^ht^K each or^nie »uh6tanc^ coa 
UUnt M important ; and it %i provided that this quaiUitkf^ 
iAovffh ind^nife^ ehail not exceed or fedl hdmo certain Um- 
ita. The truth of this propoeltion is tniide evident trom the 
following faetd : In the tirst place, all organs and tissues must 
contain a tolerably definite quantity of water to give them 
proper consistence. The evils of too grrat a proportion of 
water in the system, and consequently a diminution of solid 
elements, are well known to the practical physician. Gen- 
eral muscular debility, loss of appetite, dropsies, and various 
other indications of imperfect nutrition, are among tlie r&- 
ealtfi of snch a condition; white a detiutency of water is im- 
mediately made known by the sensation of thirst, which 
leads to ite introduction from without. 

The fact that water never exists in any of the flnlds^ semi- 
solids, or solidsj without being combined with inorganic salts, 
and especially chloride of sodium, is one reason why its pro- 
portion in various sitnations is to a certain extent constant. 
The presence of th^e salts influences, in the fieruisoHds at 
leastj the quantity of water entering into their composition, 
and consequently regulates their consistence, A very siiuple 
experiment shows this with reference to the chloride of 
sodium. If a piece of muscle be placed in a strong eohitiou 
of common ealt, as in salting meat, it becomes harder, and 
loaea a portion of its water of composition ; while ex[K»sed 
to the action of pure water, it absorbs a certain quantity and 
becomes softer. The nutrient fluid of the must^Ies during 
life contains water with just enough saline matter to pre- 
serve their normal consistence. This action of saline matters 
is even more apparent In the case of the bloLKl-eorpnscles. 
If pure water be added to the blood, these bodies Bwell up 
aud are finally dissolved; while if we add a strong soln- 
tiou of salt, thoy lose water, and I»ocoine shniiikcu and 
corrugated; but their natural form nnd consistence can 
be restored, even after tliey have been completely dried, by 



WATEB. 



adding water containing about the proportion of salt wliich 
exists in the plasma. 

It seems clear, then, that water is a necessary element of 
all tissues, and is especially important to the proper constitu- 
tion of oi^anic nitrogenized substances ; that it enters into 
the constitution of these substances, not as pure water, but 
always in connection with certain inorganic salts ; that its 
proportion is confined within certain limits ; and that the 
quantity in which it exists, in organic nitrogenized substances 
particularly, is regulated by the quantity of saJts which en- 
ter, with it, into the constitution of these substances. 

The quantities of water which can be driven off by a mod- 
erate temperature (212* Fahr.) from the different fluids and 
tissues of the body, vary of course very considerably, ac- 
cording to the consistence of the parts. The following is a 
list of tlie quantities in the most important fluids and solids : 



Table of Qwrniity of Water. 



-3 



lu 



Farta per l.OOa 
2 



•3 

5 



Enamel of the Teeth 

Epithelial Desquamatian. S7 

Teeth 100 

Bonea. 180 

Tendons (Bordach). 500 

Articular Cartilages BSD 

Skin (Weinholt) B75 

liver (FrommLerz BDd Gugert] 618 

Muscles of Man (Bibra). V2B 

Ligamento (Cheyreul). W8 

Mean of Blood of Han (Becquerel and Rodier). VSO 

Uilkof Human Female (^mon) 887 

Chjle of Man (Reea) 904 

Bile. 906 

Urine. 983 

Human Lymph Cnedemann and Gmelin) 960 

Human Saliva (Mitscberlich) 968 

Gastric Juice. 984 

Perspiration 989 

Tears '. 990 

PiUmonary Vapor. 997 



Thia table is made of selections from the table of Robin and Terdeil— titiien 
fivDU Ttrions authors. 



34 



ISTKODTTCTKOT. 



Functum of Water. — Afler -what has been stated ro- 
Bpecling the condition in wiiich water exi&ts in the body, 
there remains hut little to say concerning its function. Aa 
a conatitnent of organized tissuee, it gives to cartilage its 
eluaticity, to tendons their pliability and toughness ; it ia 
necessary to the peculiar power of resistance of the bones, 
and, as wc liave already seen, it is necessary to the proper 
cotisistence of all parts of tbe body. It has other important 
funcliouB as a solvent. Soluble articles of food are iutrg- 
duced in solutioa in water. The excrementitious matters, 
■which are generally soluble in water, are dissolved by it in 
the blood, carried to the organs of excretion, and diEcharged 
in a watery aolntion from the body. 

On'ffin and DUcJiarge of TTflrfcr. — It i9 evident that the 
great proportion of water is introdut-M from witbout in the 
fluids, and in the wntery constituents of all kjnde of food; 
but the theoretical views of some pliysiologiele with regard 
to the hydro-carbons and their combustion, led to the supposi- 
tion that water is also formed in the body by a direct onion 
of oxygen and hydi'ogen. The true way of determining this 
point is to estimate all the water introduced into the organism, 
and compare this quantity with that wMeh ib dlBcharged. The 
latter eatimatip, however, prc-sentB very great difficulties. As 
■water is continually given ofi" in the form of vapor from the 
ekinj and in the expired air, tbe q^uaiititlea thus diechai^ed 
are ^abject to great variations, dependent npou exercise, tem- 
perature, the state of the atmosphere, etc., and even if con- 
stant could be estimated with great diOiculty. Experiment& 
on this point have been uudcrtaken by Sanctorius, Carral, 
Bonssingault, and others; but ibey are npt sufficiently com- 
plete to settle tlie question. 

In tbeprcaeut state of our knowledge, we can only say 
that water is introduced with the fluid and solid elements of 
food, by the stomach, and that it escapea by the urine, faeces, 
lungs, and skin. There is no direct evidence that any is pn> 



CHLOKEDX OF BOTOCIS, 75 

dncKl in the interior of the body. In the iaane of water by 
the kidneys and skin, it has long been observed that, in point 
of activity, these two emnnctories bear a certain relation to 
each other. When the skin is inactive, as in cold weather, 
the kidneys discharge a lai^e quantity of water ; when the 
Bkin is active, the -quantity of water discharged by the kid- 
neys is diminished. Certain therapeutical agents, also, can 
be made to act as diaphoretics by combining other measures 
which favor cutaneous action ; or as diuretics, by employing 
measures to diminisli the action of the skin. 

CMoride of Sodium (Common Salt). 

Chloride of sodium is next in importance, as an inorganic 
proximate principle, to water. It is found in the body at all 
periods of life, existing, like water, in the ovum. It exists in aU 
the fluids and solids of the body, with the single exception of 
the enamel of the teeth. In the fluids, it seems to be simply 
in a state of solution, and can be recognized by the ordinary 
tests ; in this respect we may class together the chlorides of 
Bodinm and potassium. 

The quantity of chloride of sodium in the entire body 
has never been estimated ; nor, indeed, has any accurate esti- 
mate been made of the quantity contained ih the various tis- 
sues ; for all the chlorides are generally estimated together. 
It exists in greatest proportion in the fluids, giving to some 
of them, as the tears and perspiration, a distinctly saline 
taste. The following table gives an idea of the quantity 
which has been found in some of the most important of the 
fluids and solids : 

T<d>le of Quantity of Chloride of Sodium. 

PuU per 1,000. 

In Blood, Human (Lehmann). 4-210 

" Chyle (Lehmann). 6-810 

" Lymph (Naeae) 4-120 

*■ 101k, Human (Lehmann) 0-870 



B6 



nnm>DTj'CTiofr. 



I^rbperUHL 

InSolira, HumsD (Ldunun} 1 SZO 

" Pempinktinn, Human {mvan at ihrtf anilyscB, F)utti). . . . it'432 

" Drine (niarimiira) i f 'J-2&) 

•• '" (medium).. [V^limlin. ■] 4.B10 

" " (rainimttm) ) ( 2400 

" F*calM«.tteM(Berwliufi) 8-Om 

^UTUshon of Chloride of Sodium. — The fouction of this 
prineiplo h undoubtedly important, but is not yet ftillj- un- 
deretootl. It does not ficem to enter into tlie sul^stance ot" 
tlie organized solids and semisolids as an important and ee- 
eej]tial element, but apparently exercises its chief function in 
the fluids^ It certainly determiaea, to a great extent, the 
quantities of exudations, regulates ab6ori>t3on, and serves to 
maintain the albuniinoidis, especially those contained in the 
blood, in a state of fluidity. Albumen is coagulated by heat 
with much greater difficulty in a solution of chloride of 60- 
diutu than when mixed witla pure water. A stroug eolation 
of common salt ia capable of dissolving caseine, or of prevent- 
ing tlie coagulation of fibrin. We bave already alluded to 
tbo fact tbat it is tlio chloride of sodium particularly which 
re^ibites the quantity of water entering into the composition 
of the bloi^id-coqiUEC'Ies, tlicreby preser^'ing their form and 
consistence; and that it seems to perform an analogous func- 
tion with reference to the other senufiolidti of the body. 
"With regard to tlie general function of thie eub&tance, the 
following proposition of Liebig is adopted by Hobiu and Ver- 
deil, and a little rcAection will show that it is sustained, as 
far as ue know, by the faets: 

" Common saU ia intermediate in aertain general j/ro- 
cesses, and does not pai'ticlpate hy its elements in tfte foTTna- 
iion of itr^ansy 

In tlie first place, the fluids of t!ie body are g^enerally in- 
termediate in their functions, containing nutritious elements, 
which aredestincd to be appropriatcdbythetissues and organs, 
and worn-out elements, which are to be separated from the body. 
Tn the blood and chyle chloridg of sodium is found in greatest 



OHI/IBIDR 07 BODmi. 

abundance. When thenutrition of organs takes place, wlilcli 
consists in the fixation of Dew pruxmiate pnuciples, chloride 
of sodium is not deposited in auy considerable quantity, but 
seems to regulate the general process, at least to & oei'taici 
eitent. In all civilized countriL-a suit ia used extensively aa 
a condiment^ and it undoubtedly facilitates digestion by ren- 
dering the food more eaTory, and increasing the flow of the 
digestive flnids ; here, likewise, acting eiinpfy as an interme- 
diate agent. There is nothing more general among men and 
animals than this desire for common ault. The camivora 
crave it, and obtain it in the blood of animals ; the herbivora 
frequent '*' salt Ufha " and places where it fs tijund, and religh 
it when mixed witli their food ; while by man its use is 
almost nnivei'snl. lu the domi^tic herbivom tlie effect of 
ft deprivatiou of this ai"tit;le is very marked, and has beeD 
made the Btibject of some very interesting cxperimente by 
Bouasingault. This observer experimented upon two lota 
of bullocks, of three eaeh, all of them, at the time the ob- 
eerrations were commenced, being perfectly healthy and in 
fine condition. One of these lots he deprived entirely of sjilt, 
excepting Tvhat was contained in their fodder, while the other 
was supplied with the usual quantity. No marked difference 
to the two lots was noticed until between five and bix monthe, 
when the difference in general appearance was very distinct- 
The animals receiving salt retained their tine appearance, 
while the others, though not diminished in flesh, were not 6b 
sleek and fine. At the end of a year tlie dittereuee was very 
marked. The hidea of those which had been deprived of salt 
were rough and ragged, their appearance liatleas and inani- 
mate, contrasting etrougly with the sleek appearance and 
vivacious disposition of the others,' The experiments of 
Bonssingault are the most conclusive that have ever been 
instituted with regard to the influence of chloride of sodium 



1 BoDSSittOAiTLT, Mhaeim da ChimU AgrKoU et d« Fhytwhgie, P&rii, leM, 



88 



IHTEODVOnoS. 



Upon nutrition. Tliey indicate a certain deSciency in iTie 
nutrition of animals deprived of it, but not any Gonsidomble 
losfl of weight. Before these observationB were made, Dallty 
made upon twenty ebeep aualogoua esperiioents., wliicb wer^ 
continued for tbree months. At the end of tliat time the 
lut whicli received salt presented a considerable excesa of 
weight (about 22| llis.) over the othere/ 

It IB a Bigniticant fact that the qiiantitj of chloride of so- 
dium exieting in the blood la not Biibje«t to variatioDj but 
that an exceBs introduced with tlie food ie thrown off by the 
kidneyn. The quantity in the urine, then, bears a relation to 
the quantity introdueed as food, bnt the proportion in the 
blood ia constant. Tliis is another fact in favor of the view- 
that the presence of n definite quantity of common salt in 
tl^e cireulating fluid is essential to the proper perlbrmance ot 
the general function of nutrition. 

Origin emd Discharge of Chloride qf Sodium. — Thia 
substantive is always introduced with food in tlie condition 

in -which it is found in the body. It la contained in the sub- 
stance of all kinds of food, animal and vegetable; but in the 
herbivora and in man, this Bource is not euSicient to supply 
the wants of the system, and it is introduced, therefore, as 
salt. Tho quantity which ia discharged from the body has 
been eatimated by Bnrral' to be somewhat lesa than the 
quantity introduced, about one-fit\li disappearing; bnt these 
estimates are not exactly accurate, for the ainouut thrown off 
in perepiration has never been directly ascertamed. It eiista 
in the blood in connectiou with the i>liosphate of potaBsa, and 
a certain amount id lost in a double decomposition whicIi 
takes place between these two salts, resulting in the fonua- 
tioQ of chloride of potasBium and phoei>hate of eoOh. It also 
ii &up])Osed to furnish the soda to all the suite which have a 

' LoNorr, Train dt Phijriolo^ Piri*. ISUe. totoe i., p. 80. 
* (Ited bf Robin anil Tbrdkii. CAimU ^rw/OoiJ^ ef PAjitiolo^ijiui^ Tattg, 
1609, tome ii., p. 1B». 



OHLOBIDE OF POTAfiSiniC. 30 

Boda base, and a certain quantity, therefore, disappears in this 
way. 

Existing, as it does, in all the solids and fluids of the 
body, it is dischai^ed in all the excretions, being thrown off 
in the urine, facee, perspiration, and mucus. 

Chloride of Potassivm. 

Chloride of potassium, though not as important a proxi- 
mate principle as the cliloride of sodium, nor so generally 
dlBtribnted in the economy, seems to have an analogous 
fimction. It is found in the Muscles, Liver, Milk, Chyle, 
Blood, Mucus, Saliva, Bile, Gastric Juice, Cephalo-Rachidian 
Fluid, and Urine. It is exceedingly soluble, and in these 
sitnations exists in solution in the fluids. 

Its quantity in these situations has not been accurately 
ascertained, as it has generally been estimated together with 
the chloride of sodium. In the muscles, it exists, however^ 
in a larger proportion than common salt. In cow's milk, 
flkimmed, Berzelius ' found VI pts. per 1,000 ; Pfaff and 
Schwartz, 1-35 per 1,000 in cow's milk, and 0-3 per 1,000 in 
human milk.* 

Of the function of this principle, little remains to be said 
after what has been stated with regard to the chloride of 
sodium. Their fimctions are probably identical, though the 
latter, from its greater quantity in the fluids, and its univer- 
sal distribution, is by far the more important. 

Origm cmd Discharge of CMoride of Potassium. — This 
mbstance has two sources ; one in the food, existing, as it 
does, in muscular tissue, milk, etc., and the other in a chem- 
ical reaction between the phosphate of potassa and the 
chloride of sodium, forming the chloride of potassium and 

' Sncos, Chanittry of Man, American edit, p. 842. 
* RoBiR R VtKDKiL, op. tit, tome iL, p. 200. 

^ 



40 



JCcnoN. 



tbe phosphate of soda. That thk (iecomposition tates place 
in the bodj, k evident from tbe fact that the ingestion of & 
considfraMo quaatity of common salt has been found, in the 
sheep, to increase the qHantity of chloride of potasBiUDi in 
the urine, without havjng any influence on the amoiint of 
thioride of sodium. The chloride of potassium is distharged 
from the body in the urine and mucus. 

I^hospliate of Zime. 

Phosphate of Lime is found in all the solids and fluids of 
the body. As it is always united, in the solids, with organic 
BubetanceB as an important element of conatitutlan^ it ia 
hardly second in importance to water. It diflere in its fiinc- 
tioDS to essentially from the chlorides of Bodium and potaa- 
iium, that tliey are liardJy to be compared. It ia Insoluble 
in water, but held in Bolution iu tbe fluids of the body by 
virtue of free caj'lwnic acid, the hiearbouates, and tbe chlo- 
ride of sodium. In the solids and eemieulids, the condition 
of its exiBtence le the same as that of water; i. e. it is incor- 
porated, particle to particle, with the orjjauic substance char- 
atterifitic of the tisane, and is one of ittj essential elements 
of compoftition. Nothing need be added here aa to this mode 
of anion in the body of organic and inorganic Bubstances^ 
after what has been said under tbe head of watev. 

The following table ' gives the relative quantity of phos- 
phate of lime in varioos Bituationa: 



TdhU of Quaidiiy of I*hospAaie qf Lime. 

Pub par l,0(ia 

" Vcnoua Blood, j ( 0-7M 

" Milk, UiiniB.n ^Pfoff tJxA Sctwam).. 2*600 

" SiUiT« (Wright) 0-600 



' SclwlioM rroin the Ubie of Robin aod VlTtlell, op. **t 



FHUSPEATE OF LIME. 41 

Fvti p«r 1,00a 

la Urine (proportion to w^ht of ash, Fleitmann) 25-700 

« Excrements (Beraeliufl). 40-000 

" Bone (Laaaaigne). 400* 

" Vertebr* of a rachitic patient (BoBtock) 186- 

" Teeth of Infknt one day old. ^ 

" Teeth of Adult 

" Teeth, at eighty-one yeftn. . 
" Enamel of Teeth 



Laeeaignc' 



610' 
610- 
6«0- 
880- 



By this table it is seen that the phosphate of lime .exists in 
very small quantity in the fluids, but is abundant in the 
Bolids. In the latter the quantity is in proportion to the 
hardness of the structure, the quantity in enamel being, 
for example, more than twice that in bone. The variations 
in quantity with age are very considerable. In the teeth 
of an infant one day old, Lassaigne found 510 parts per 
1,000; in the teeth of an adult, 610 parts; and in the teeth 
of an old man of eighty-K)ne years, 660 parts. This increase 
in the calcareous elements of the bones, teeth, etc., in old age 
is very marked ; and in extreme old age they are deposited in 
considerable quantity in situations where there existed but a 
small proportion in adult life. The sjstem seems to grad- 
ually lose the property of appropriating to itself organic mat- 
ters ; and though articles of food are digested as well as ever, 
the power of assimilation by the tissues is diminislied. The 
bones become brittle, and fractures, therefore, are common at 
this period of life, when dislocations are almost unknown. 
Inasmuch as the real efficiency of organs depends on organic 
matters, the system actually wears out, and this progressive 
change finally unfits the various parts for the performance of 
their functions. An individual, if he escapes accidents and 
dies, as we term it, of old age, passes away thus by a simple 
wearing out of his organism. 

function of Phosphate of Lime. — This substance, as be- 
fore remarked, enters largely into the constitution of the 
Bolida of the bodv. In tbe bones its function is most appa- 



42 



DTTBaDCCnOH. 



pent. It3 existence, in gnitable proportion, is necessary to the 
meclmnical office of these parts, giving iLem their power of 
resistance, without rendering them too brittle. It la more 
flbundatit in the bonca of the lower estreniities, which 
have to Bu&tain the weight of the body, "than in tJuo&e of tlio 
upper extremitiea ; and in the ribs, which are elastic rather 
than resisting, it exists in leas quantity than in the bones of 
the arm. 

The neeeasity of a proper proportion of phosphate of lime 
in the bones is made evident by eases of disease. In rachi- 
tis, where, aa is &een by the table, its quantity is verj tntich 
diminished, the boDffi are unable to sustain the weight of the 
body, and become deformed. Finally, when the phosphate of 
lime is depoeiteil, they retain their distorted shape. The 
phos]>hate of lime may be extracted from the bones by ma- 
ceration in dilute hydrotthloric acid, wliich disaolvea it, leav- 
ing tnly the organic substance. Bones treated in this way, 
though they retain their form, become very pliable ; and a 
lung slender one, like the fibula, may be actnally tied into 
a knot. 

Ori'/in and Disf^harge of Pho»pkaU of Lime. — The ori* 
gin of this principle ia exclusively from the external world. 
It enters into the constitution of our food, and is discharged 
with the fsecea, urine, and other matters thrown oH' by the 
body. Its quantity in the nrine is exceedingly variable, Le* 
canu found from 0'437 to 29-250 grains thrown oft' by the 
kidneys during the twenty-four hours.' 



Carbonate of Litm. 

Carbonate of lime exists in the Bones, Teeth, Cartilage, In- 
ternal Ear, Bloody Sebaceons Matter, and sometimes in the 
tjrine. It exists as a normal constitnent in the urine of some 
herbivora. but not in the carnivora, nor in man. It is most 

' LuuLiiiH, PAi/tiotoffieal Chanittrify Amerieen Cditioo, toI. IL, p. 15L 



CABBONATB OF IJUE. 43 

appropriately considered immediately after the phoBphate of 
lime, because it is the salt next in importance in the consti- 
tution of the bones and teeth. In these structures it exists 
intimately combined with the organic matter, under the same 
conditions as the phcMphates, and has analogous functions. 
In the fluids it exists in small quantity, and is held in solu- 
tion by virtue of free carbonic acid and the chloride of po- 
taasium. 

The carbonate of lime is the only example of an inor- 
ganic proximate principle existing uncombined, and in a 
crystalline form, in the body. In the internal ear it is found 
in this form, and has a function connected with audition. 

According to Robin and Verdell, it is possible that in 
chemical analyses a certain quantity may come from a 
decomposition by calcination of those salts of lime which 
contain a combustible acid.* These authors give a table 
of the quantity of this Bubstance in various of the solids 
and fluids of the body, fr^m which we make the following 
selections : 

Table of Qtianti^ of Carh<m<Ue of Lime. 

Ptftap«r],O0a 

la Bone, Human (Berzelius) 118-00 

" " " (Marchand) 102K>0 

" " « (Laasaigne). 76-00 

" Teeth of Infant one day old. \ /... HO-00 

" Teeth of Adult [■Laasaigne) ... 100-00 

" Teeth of Old Man, eighty-ono yeare ) { . . . 10-00 

" Urine of Horae (BouBefaigaBlt) 10-82 

Origin and JHscJiarge of CarbonaUi of Lime. — Carbonate 
of lime is introduced into the body with our food, held in so- 
lution in water by the carbonic acid, which is always present 
in small quantity. It is also formed in the body, particularly 
in the herbivora, by a decomposition of the tartrates, ma- 

' Op. at., ToL a., p. 247. 



H: ISTBODrCTION. 

lat(}3, citrates, and acetates of liine contained in the food. 
Tljese ealta, meeting with carbonic acid, ase decomposed, and 
the carbonate of ]ime is formed. It is probable that in the 
human sulijeut snme of it ie changed into the phosphate of 
lime, and in thi» furm ia discharged in the urine ; hut ■when 
and Iiow this change takes place has not been detinitely as- 
certained, 

CarlMnafe &f Soda. 

Carbonate of soda is found lu the blood and Ballva, giv- 
ing- to these fluids their alkalinity ; in the urine of the hu- 
man fiuhject, when it is alkaline without beini,' amiuoniacal ; 
in the urine of the Jierbivora ; in the lympli, cephalo-radiid- 
ian fluid, and bone. The anfllysca of chemiata with regard 
to this substance are very contradictory, on account of its 
formulion during the process of incineration ; but there ia no 
doubt that it ie found in the above flituations. The follow- 
ing table gives the quantities whicli have been found in some 
of the fluids and Bolids : 

Table of Quantity of Cai^mmie qf Soda. 

Puts per 1,000, 

In Blood of the Ok (¥arcel) 1-62 

" Lymph (Nas»e) 058 

" CepWi>meliIilian Huid (Ijas^aipat') .,..., O'BO 

" Compnel TissQc of Tibia in Male of 38 years (Vfllentin) £'0O 
** Spon^TiaauQof thO'SiuucCValeiitiii). ., 0'7<> 

Function of Carbonate of Soda. — This substanee has a 
tendency to maintain the flnidity of the fibrin and albumen of 
the blijod, and ai-ftists in preserving the form and consistence 
of the hlood-cori'o&clee. Its function with regard to nutri- 
tion i& rather accessory, like that of chloride of sodium, than 
essential, tike the phosphate of lime in the constitution of 
certain structurea. 



UA0NE8IA, ETC. 45 

Origin and Discharge of Carbonate of Soda. — This pub- 
Btance is not introduced into the body as carbonate of soda, 
bnt is formed, as is the carbonate of lime in part, by a do- 
composition of the raalates, tartrates, etc., which exist in 
fruits. It is discharged occasionally in the urine of the hu- 
man subject, and a great part of it is decomposed in the 
lungs by the action of pneumic acid, setting free carbonic 
acid, which is discharged in tlie expired air. 

Carbonate of Potassa. 

This salt, as a proximate principle, is found in -greatest 
abundance in herbivorous animals. It also exists in certain 
quantity in the human subject when subjected to a vegetable 
diet. Under the heads of function, origin, and discharge, 
what has been said with regard to the carbonate of soda will 
apply to the carbonate of potash. 

Carbonate of Magnesia — Bicarbonate of Soda. 

It is most convenient to take up these two salts in con- 
nection with the other carbonates, altliougli they are put at 
the end of the list of inorganic substances, as the least im- 
portant. We know very little with regard to the function 
■which they have to perform in the ecouomy, which is prob- 
ably quite insignificant. Traces of carbonate of magnesia 
have been found in the blood of man, and it exists normally 
in considerable quantity in the urine of herbivora. In the 
human subject, it is discharged in the sebaceous matter. 

Liebig has merely indicated the presence of bicarbonate 
of soda in the blood, but we have no definite idea of its func- 
tion in this fluid. 

Phosphate of Magnesia — Neutral Phosphate of Soda — 
Phosphate of Potassa. 

These salts are found in all the fluids and solids of the 

4 



46 INTEODDCnoN. 

body, althougli not existing in a very large proportion, as 
compared with the phosphate of lime, which we have already 
considered. In their relations to organized Btmctures, they 
are analogous to the phosphate of lime, entering into the 
composition of the tissues, and existing there in a state of 
intimate comhination with their nitrogenized constituents. 
They are all taken into the body with food, especially by 
the camivora, in the fluids of which tliey are found in mnch 
greater abundance than the carbonates; which latter, as we 
have already seen, are in great part the result of the decom- 
position by carbonic acid of the malates, tartrates, oxalates, 
and other salts of vegetable origin. 

With respect to their functions, we can only say that, 
with the phosphate of lime, they seem to bo necessary con- 
stituents of the organized structures. 

They are discharged from the body in the urine and 
faces. 

SidjfKate of Soda — Sulphaie of Pota^a — Sulphate &f 

Lime. 

The sulphate of soda and the sulphate of potassa are 
identical in their situation, and, apparently, in their fnnctions. 
They are found in all the fluids nnd solids of the hodv, ex- 
cepting milk, bile, and gastric juice. Their origin in the 
body is from the food, in which they are contained iu small 
quantity, and they are discharged in the urine. Their chief 
function appears to be in the blood, where they tend to pre- 
serve the fluidity of the albuminoid matters, and the form 
and consistence of the blood<'orpu8cle8. 

The sulphate of lime is found in the blood and fEcces. It 
is introduced into the body in solution in the water 'which 
is used as drink, and is discharged in the fcecee. 

Its fimction is not understood, and is probably not very 
important. 



SUHUASr OF CfOBOAKIO PSIN0IPI.E8. 47 

Hijdrochlorate of Ammonia. 

This enbstance bae Bimply been indicated by cbemiets as 
existing in the gastric juice of raminantB, the saliva, tears, 
and urine. Some cheipists make a rearrangement of its 
atoms, calling it chloride of ammoniam, when, instead of 
NH., HCl, it would be NH.a. 

It is discharged in the urine, in which it exists, according 
to Simon,' in the proportion of 041 parts per 1,000. Its 
origin and function are unknown. 

Summary. — A review of the functions of the individual 
inorganic constituents of the body, excluding the gases, will 
show that they may be divided into two groups : one, which 
is composed of those substances, existing particularly in the 
solids and semisolids, whick are in a condition qfmolecidar 
union with organic suhstanceSj merge their identity, as it 
tcere^ into them, and become necessary constituents of t?m 
tissws ; and the other, composed of substances which rather 
regulate, hy their influejwe in endostnoais, or otherwiee, the 
nutritive processes, do not seem to he indispensable constituents 
of the tissues, hut have rather an accessory office to perform 
in the function of nutrition. 

At tjie head of the first group we may place water ; the 
absence of which involves destruction of the proJ)erties of 
the tissues, and even of the organic elements. 

At the bead of the second group we may place common 
salt; which is absolutely necessary to the functions of nutri- 
tion, tbougli it does not seem to form an indispensable ele- 
ment of the tissues. 

The first group, as we should naturally expect, forms a 
considerable proportion of the body, and the articles compo- 
sing it are discliarged in small quantity ; as in the case of 

' SiMOS, Animal Chemutry, vilh Rtferener to tkt FHtfioloffy and PaHutoffif 
tjf Jfan, rbiladelphia, 184«, p. 403. 



49 csTBODUcnow. 

water, which composes two-thirds of tlie entire organism, aud 
yet only about four and a hall' pounds are discharged daily 
from the skin and lungs, and in the urine and faeces. 

The second group enters and is discharged from the body 
in considerable quantity, and very Kttle remains in the or- 
ganism; as common salt, which exists in the urine in a 
greater proportion than in any of the solids or other fluids. 

The following are the inorganic substances which ai-e ap- 
parently indispeusable to the constitution of organized tissues : 

Water. 

Sasic Phmphate of Lime. 
CarhonaU of Lime. 
Pho^hate of Magnesia. 

" " Soda. 

« " Potasaa. 

The following are those which appear to have an accessory 
office in nutrition : 

Chloride of Sodimn, 

" " Potassium, 
Carbonate of Soda. , 

Bicarbonate of Soda. 
Carbonate of Potasaa. 

" " Magnesia. 
Sulphate of Soda. 

" " Potassa. 

The remaining two principles, sulphate of lime and hy- 
drochlorate of ammonia, are so obscure in their function that 
they cannot be definitely put in either of the above groups. 

OEGANIC NON-NITHOGENIZED PRINCIPLES. 

{Sydro- Carbons.) 

The principles of this class differ widely from inorganic 
Bubatances In the first place, they have a dififerent origin, 



SDOABS. 49 

being formed exclusively in animal or vegetable bodiee. Tbey 
are of definite chemical composition and cryetallizable. The 
most important groups of this class j viz., the sugars and fats, 
are composed of carbon, hydrogen, and oxygen. The sugars 
are sometimes called Hydro-Carbons. They are distinguished 
from another class of organic substances by the fact that 
they do not contain nitrogen ; which has given them the 
name of Non-nitrogenized Principles. They are in part 
introduced into the body as food, and in part formed in the 
economy by special organs. In the former instance, they 
undergo an elaborate preparation by digestion before they 
become part of the organism, differing in this respect from 
the inoiganic principles, which are absorbed nnchanged 
With the exception of butter and the sugar of milk, they are 
never discharged from the body in health, but disappear in 
the processes of nutrition. In this respect, also, they differ 
from the inorganic principles, all of which are discharged 
fivm the body, most of them in the condition in which they 
entered. 

The mtffit import.ant principles of this class may be divided 
into two great groups, the Sugars and the Fais; in addition 
to wbicli we have, lactic acid and the lactates, pnenmic acid, 
pnenmate of soda, the fatty acids and their combinations, 
and certain oi^anic salts which are found in the bile. 

Sugars. 

The varieties of sugar with which we are most familiar, 
of which cane-sugar may be taken as the type, are not 
found in the animal body, but belong to the vegetable 
kingdom. These, which form an important element of 
food, must be modified by digestion before they become 
proximate principles. For a long time it was supposed 
that sugar was an exclusively vegetable" production and 
consumed by animals; but late experiments, especially those 
of Bernard, have shown that sugar is constantly produced by 
animals, presenting, in this instance, marked differences from 



50 



the vegetable varieties. Vegetable sngnr lakcu as food u 
changed eo as to reseDible animal BUgar, before it is absorbed. 
Ill considering, tlicn, tbe proximate prin4'iples of the body, 
■we have only to do with the animal Bogars. 

There are two varietiea of eiigar mannfactnred in the 
economy. The tirat 13 constantly formed by the liver, and 
ia fonqd in t!ue oig-an and the blood whiob circulatea between 
it and the hmgs. This variety is called Liver-eugar ; and, as 
it appears iu the uriae of diabetics^ i» soiuetimes known un- 
der the name of diabetic sugar. The second variety is only 
present in the organism during lactation. It exists in the 
milk, and is calted Milli-sngar. We have also engar resnll- 
lug from the transfonnation by digestion of cano-eugar and 
Btarch, which is called Glucose. This resembles the Hver- 
Bugar very closely, and ts, indeed, identical with it in cotnposi- 
tion, but differs from it in the tact that it ferments lees eudly. 

The presence of sugar in the economy seems to be a ne- 
cesaily of existence. It, or starch which is readily converted 
into glacose, cottstitutefi an important jujd necefisary element 
of footl. In early life large fniantities are taken ia with the 
milk. This, however, does not seem to be sufficient to supply 
the wants of the system, and we have it continnalty manufac- 
tured in the interior of the body ; bat one* fonneiJ, or intro- 
duced from without^ it undei^oe^ some transformation in nntri- 
tion, and is never discharged in healths Sugar is exceedingly 
Bolnble, and in thy economy, exists in solution in the blood. 
Here it forms a union with the chloride of sodium, which 
masks, to a certain extent, some of its characteristic proper- 
ties, 6uch as the peenliar taste by which it is so readily 
rec<^aized. 



Contjkmiton and Propa-itit, — The sugars are compoeed 
of carbon, hydrogen, and oxygen ; and it is noticeable that the 
hydrogen and oxygen always esis-t in equal proimrtions, or 
in the proportions which form water; a peculiarity affording 
an explanation of the transformation of one varietur' of sugar 



8UOAB6. 61 

into anotlier, which is effected in some inBtaiices with great 
facility. 

Simon ' gives the following composition of the animal 
eiignre in a crystalline form : 

Liver-Sugar and Glucose, C„H„0„. 
MUhSugar, C„H„0„. 

On exposing either of these varieties of sugar to a dry 
heat, two atoms of water of crystallization are driven off, 
leaving tlio formnla for liver-sugar, C„H„0,„ and for milk- 
sugar, C,JI„0,,. From the relative eomiwBition of these 
varieties of sugar, it is seen that the addition of two atoms 
of hydrogen and oxygen, or water, to milk-sugar, will trans- 
form it into glucose. This change actually takes place in 
digestion. The digestive fluids act also upon cane-sugar 
(C„H„0„) and starch (C„II„0„), transforming them into 
glucose. 

Animal sugars are distinguished from cane-sugar hy 
their different behavior in the presence of acids and alkalies. 
Cane-sugar is converted into the animal variety by boiling 
for a few seconds with a dilute mineral acid, and is nnaffected 
by boiling with an alkali ; while the animal sugars are not 
affected by acids, and are transformed into a dark-hrowa 
substance, melnssic acid, by boiling w^ith an alkali. 

If a solution of sugar be mixed ^"ith a little fresh yeast 
and kept for a few hours at a temperature of from 80* to 
100° Fahr., a peculiar change takes place which is called fer- 
mentation. The sugar is decomposed into carbonic acid gas, 
which rises to the top in bubbles, and alcohol, which remains 
in the liquid. Some ferments, especially organic matters in 
process of decomposition, when they exist in a saccharine 
solution, have the property of inducing a change of the sugar 
into lactic acid (C^,0,), giving rise to what is called the 
lactic-acid fermentation. This process is peculiarly intercst- 

* SiMOH, Chemitiry 0/ Man, PhikdelphU, 1848, p. 64. 



52 



iKTRoDrcnos-. 



ing iu a physiological point of view, from the fact tbat much 
of tJi6 fiiij^ar wliicli diaippeiirs in [Lc ecoiitmij is nuw tbuught 
to nncToi'go Ibis ehange. 

A clear eolntion of augur hiis a peculiar effect upon jvolar- 
ized light, being possessed of what is called a rotatory power. 
If a ray of polarized lijiht be passed througli a tulie euntaJn- 
ing simple water, it* du'ettion la unehauj;ed ; hut il" a eacchii- 
rjoe Foliitioii bo 8ub&titiite<], it ie found to possess «hat. ia 
called molecular activity, and turns llie ray to the right. The 
luuount of deviation, whieU can eaaiJy be measured by an 
instrument constructed for this purpose by Biot and Soleil, 
called il pohLri meter, ludieates the qimntity of huga.r iti the solu- 
tion. Tiie inatrument above mentioned \& soraetiiues usetl 
for quantitative analysis. 

Te«t4 fw Sugar. — Bellable te&ta for determining the 
presence of ewgar in the aniiual tissues and fluids are useful 
to the practical physician as well as the physiologist; for 
this, substance frequently occurs iu the urine, ns a pathological 
couditiun, when it is essential to aseertaiu tiie fact of its 
prcscTice, even if no attempt be made to determine ita quan- 
tity, i'ur this purpose n number of tests have been devised, 
wliich are most of them reliable and simple of application. 

Moore^ij or tfte Potask-TeM. — This teat depends on (be 
convorsinn of the auiinEi] Migars into mehissie acM by boiling 
with u, caustic alkali. It is employed in the following way: 
To II small portion of the suspected liquid in a test-tube we 
add a little caustic ["otasb in solution, and boil the mixture. 
If supir he present, a brownish color will be produceil, its 
intensity depen(3ing upon the quantity of sugar. This test 
is appliealile only to glucose, grape-sugar, and the animal 
Torietiea. 



Tromm^^s Test. — This is one of the moat delicate and 
con veti it'll t testa for sugar. It is employed in the following 



6CQARS. 53 

way : To the Buapected liquid in a test-tube, we add on£ or 
two drops of a moderately etrong solution of eulpiiate of 
copper, and render the mixture distinctly alkaline by tlio 
addition of caustic potash in solution. On the addition of 
the alkali the mixture will assume a distinctly blue color, 
especially marked if sugar be present. On the application 
of heat, if sugar be present, a little before the liquid reaches 
the boiling point, a yellowish or reddish precipitate will 
begin to show itself in the upper part of the test tube, which 
as the heat continues will gradually extend through the whole 
of the liquid. If no sugar be present, the liquid will retain 
its clear blue color, unless the boiling be jirolonged, when a 
black precipitate of the black oxide of copper is likely to 
appear. In this test, before the heat is applied, the copper 
exists in the form of the sulphate of a protoxide which is 
Bolttble; but on boiling in an alkaline solution, the sugar 
becomes oxidized, is transformed into an acid, the nature 
of which is not well determined, and the copper, by losing 
an equivalent of oxygen, becomes thereby reduced to the 
condition of a suboxide, which has a reddish or yellowish 
color, and is insoluble. This is the way in which the test 
is generally employed. Trommer recommended (1841), with 
special reference to examination of urine, to first add the 
solution of potash, then filter, and then add the solution of 
copper. If sugar be present, a reduction of the suboxide will 
take place spontaneously in a few hours, or may be produced 
immediately by boiling. This removes certain sources of 
obscurity in examining tlie urine, which result from a pre- 
cipitate produced by the simple action of the potash, and not 
dependent on the presence of sugar. 

If care be taken to employ the following simple precau- 
tions in the application of this test, it will be found the moet 
reliable and simple of any that are in use for qualitative 
analysis. 

The solution to be examined must be clear. A clear 
extract of the blood, muscles, or liver, is easily made in the 



54 



IH'IUODUOnOF. 



fwHowing waj : The blooO, or tisisue, finely divided, is boiled 
witb a little water nnd sulphate of soda. la a few raomenta 
the organic aoii coloring matters will bepoiue t^oagulatod, 
when it is to be thrown on a filter, and a clear extract will 
pass through. Thia extract will eontain sulphate of soda, 
which is very soluble in hot water, but this does not interfere 
•with the application of the test, The aarae resuU may b* 
obtained by boiling with animal eharcoal, eaough being 
added to make a thiu paste, and Altering; a process, how- 
erer, which ia more tedious and has no adrautages over the 
one just descriljed. 

In testing the urine, a light flocculent precipitate will 
generally be obtained, though no sugar be present. With 
a little experience this may be distinguished from the 
deposit of Buboside of copper, by the fact that it ia less 
highly colored, and appeare in ftakea alter it finally settles 
to the bottom of the test tube, of a light grayish color; 
wliiile the suhoside of copper settles to the bottom in the 
form of a heavy red powder. If there be any doybt ta to 
the nature of the reactton, the uritie tufij be punfie*.! in va ' 
rions wuys before testing. A very simple, and perhaps the 
best method, ia to make a paste with animal charcoal and 
iilter. Ilobin recommends the following process: "To be 
certain of the presence of glucose, we free it (the liquid) from 
all reducing matters; IbI^ adding to the urine an excess of 
the neutral acetate of lead, then liltenng; 2d, adding to this 
clear filtered liquid, amnionin, until it is elightly alkaline, 
and fi,Itering. We can thL-n treat the second liquid with'tht* 
reagents ; aod if it precipitates, it is certain that there U eogar 
iuthe urine.'" Another method is to evaporate the urine to 
the consistence of a eyrup, estraet this with alcohol, drivo 
off tije alcohol by evaporation, and dissolve the residue ia 
water; when if etignr be present it will i-espond to the test. 



' Lirtn^ EI RoBiM. Dinhnnaire Jt mfAriae, ?ari», 1873, Arti«;l«j jbtmi;, 
Tliis pM('C£d id Jcacribcd oa pAgv H^4. 



8U0ABB. 55 

It is a curious fact that sugar added to healthy urine, even 
in large quantity, will not respond to Trommer's test, on 
account of organic matters, which interfere with the reduc- 
tion of the copper. The cause of this intoiferenee we do not 
understand ; but, in diabetes, the organic substances, whatever 
they may be, are not present, or at least do not interfere with 
the application of testa for sugar, especially if the quantity 
of sugar be considerable. 

Feldvng'% Test. — This is one of the most reliable and 
delicate tests for sugar, and is specially valuable in its ap- 
plications to the urine. The test-liquid, however, is liable 
to alteration by keeping ; but this difficulty may be obviated 
by preparing the three liquids and keeping them in separate, 
bottles, mixing them for use as required. The mixture will 
keep for four or five days. The three solutions are pre- 
pared as follows : 

1. Solution of crystallized sulphate of copper, 94-73 grains 
in an ounce of distilled water. 

2. Solution of neutral tartrate of potash, 378'91 grains 
in an ounce of distilled water. 

3. Solution of caustic soda, specific gravity 1'12 (about 
IGJ" of Baum6's hydrometer). 

To prepare the test-liquid, take half a fluidraehm of the 
copper-solution, add half a fluidraehm of the solution of 
tartrate of potash, and add the solution of caustic soda, to 
make three fiuidrachms. 

For ordinary qualitative analysis, boil a little of the test- 
liquid in a test-tube and then add the suspected solution 
drop by drop. If sugar be present, there will be a precip- 
itate of the suboxide of copper. If we add in this way a 
bulk of the suspected solution about equal to the volume 
of the test-liquid and bring the mixture to the boiling-point 
again, without a precipitate, no sugar is present. This liquid 
may also be used in quantitative analyses.' 

* See ToL iii., Secretion, p. 801, 



&6 



INTBODUCTIOS'. 



Harre^viTs Test. — The sohition may be prepnred aecortl- 
iiig to tlie following formula, reduced to gi'iiins from the 
formula given by Bernard i ' 

Of bitartrate t<f pota&li, 3vi. gr. ?cxijj. 

Of erjfitaliized earljoDate of soda, " v. gr. is. 

Dissolve in 3 vss. of water ; add to the solution Z iij. gr> 
li. of sulphate of copper, and Ijoil ; allow the mixture to 
cool and add 3 v. gr. is. of potush dissolved in 3 '^' ^'^ water. 
Add water till tho whole measures ; xvii. 

Maumene'a Test. — Bottler's Tfd. — The first of those 
tests is employed by saturating strips of some woolleu tissue, 
Eiich as flannelj witli a strong solntion of bifliloride of tin, 
and djying. One of theee etPipa {& moisstened with the sus- 
pected liquid, and dried quk^kly by tbe heat of a tire or lamp. 
If Btigar bo preseutj the strips will assmne a brownish or black 
tint. 

Bottler's test depends upon the redaction of a salt of bjft- 
miilh, analogous to tbe reduL-tion of the copper in Trommer's 
test. It is LMnployed in the i'ollowiug way ; We add to tbe 
suspeeted liquid a itw drops of a weak solution of the nitrate 
of bismuth in nitric acid, render the whole alkaline by tlie 
addition of a solution of carbonate of soda, and boil for three 
or four minutes. If sogiir be presenlj the bismuth will be 
reduced, and form a diu'k precipitate. Neither of these tests 
presents any advantage over Trommer's test, whicli is the one 
most geuendly employed. 

Fenneniutlon-Tesi. — Witli the eseeption of actual es- 
tractiou, this is tlie most certain test for sugar, aud should 
always be employed when the other tests leave any doubt 
with rcgiird to its pi^cscnee. It depends on a property of 
sugar whereby it is deeotuposed into alcohol and carbonic 
acid in the presence of eertaiu ferments, at a moderately ele- 
vated temperature. The test is applicable to all varieties ol 

' DkrMAUIj JLofOnt da rkyioloffU Exf)iriir.tntaU, PuriK, ISfib, p. S4. 




BDOABS. 



^7 



iDgnr ; Irat it mast lie remembRred tlmt milk-sugar fer- 
iiieiiU slowly imil with difficQlty. In its application, all that 
15 necessary ie to ndd a few drops of fresh jeast, and keep 
the saj[>C(;ted liquid for a few lioure at a temperature of fi-oiu 
80* to iCO" Falir. TLe mixture $lioul J be placed in eonie appa- 
rfttua by which tlie gas which furuiB may he eollerfed iind an- 
alyzed. To eliiiKt this, we may till a large test-tube andinvert it 
jc a small shallow vessel ; or if there he hut a small quantity of 
liquid, wo may use a very simple and convenient apparatus 
described by Bernard. This is simply a large test-tube fitted 
with II good cork, perforated to altuw the paasage of a small 
ttibe which extends t^ the bottom. This tube may be turned 
up at the lower end, and bent ubove eo as to permit tbe 
escape of the liiiuM na the gas is fijrmed. Thu whole ja com- 
pletely filiod with the suspected bolutiou, to whicli huve been 
a.dde<] a few dwi^ra of fresh yeast, and kept at a teiiiiwraturo 
of 80° to 100° Fahr. If sugar be present, bubbles of gaa will 
Boon begin to appear, which will eotleet at the top and force 
a portion of the liquid out by the BUiall tube. If no gas has 
appeared at the eud of four or six liours, it Ib cei-tain that tio 
BUgar is present. TMa test is conclusive, if proper care be 
taken in its application ; and to insure accuracy, it is well to 
test the ycBRt with a eacchariue solution to deruonstfnte its 
stirity, and test it also with pure water, to be Bure that it 
itains no sugar. We may then demouBtrata that the gas 
produced is carbonic acid by removing tlie cork and inserting 
a lighted tai)er, which will be immediately extinguished, or 
passing it into another vessel and agitating with lime- w liter, 
ivbieh wlU he rendered milky by the formation of the iunolu- 
ble carbonate of lime. The alcohol remains in the liquid, 
from which it may be separated by earefiil distillation. 

Measures for demunatrating tlie composition uf the gas 
and the preseuce of alcohol in the liquid are by Bo means 
neeeesary in tlie ordinary application of the test. The dis- 
tinct formation of gas Id the liquid is generally Buffif.jent 
evidence of the presence of sugar. 



58 



nTRODCCnON'. 



Tontli. — Another teat of the presence of su^r U tlie 
growth of tlic Toruli txrevisia'. After diabetic urine haa 
Btood for fiome time at a moderate tempemtitre, n delicate 
Bcuni will form upon the surface, whicli, on mliTosoopie 
examination, will he fimnd lo consist of a vegeiiilile ^Towtb, 
prosonting a uctmbcr of oval joints irregularly connecteii. 
These are called Turttli. After a time they break up and 
fall to the bottom of the vessel, as minute oval spores. Thia 
appearance is observed even when a small quantity of sugar 
is present, 

Yarioiis modes of procedure have beeo described for tho 
determination of the quatjtities of sugar. In general tenna 
it may be statetl tlmt the copiousness of the precipitate iu 
Trouiraer*s teat, and the amonnt of pas evolved ia the fer- 
mentatioD test, give some idea of the quantity of sugar 
present. For direetions for accurate quantitative analysis tho 
reader is referred to works on or^nic cIiemLotry. 

Origin and Funeiiom of Sugar. — Sugar is an important 
element of food at all periods of lite. In the young child it 
is introdueod in considerable qu^intity with the milk. In 
the adult it is introduced partly in the lorm of cane-sugar, 
bnt mostly in the form of fitarch, which is converted into 
sugar in the process of digestion. With the exception of 
milk-eugnr, wliich ia present only during lactation, ull tlie 
6ugar ill the body exists in a fom; re&embUng glucose, into 
which milk-sngiif, caiie-siigiir, and starch are all convened, 
either before they are absorbed, or as Ihey pass tlirough the 
liver. In addition to these exteninl sources of eugiir, it i^ 
continually raanufiictured iu the economy by the liver, 
whence it is taken up by the hlo<>d paa&ing through this 
organ. It disappears from the blootl iu its paaKige through 
the lungs. Sugar is fonnd ilien in tlie economv con- 
stantly, in the substauce of the liver, in the blood coining 
from the liter, and iq the blood of the right side of the 
beartj and after the ingestion of saccharine or aiuylaoeoni 



BUQARS. 



59 



■iticles uf Ibofl, in tlie bli>oil of tlie portal vein. It is not 
fonnd in other organs, uur doea it normally exifit in tJae 
arterial blood. 

During the first tlirco or fonr months of fostal life sugar 
is formed bj the placenta, aad exists in flU the fluida of tlie 
foetuB, in greater quantity even than, after birth. At tLe 
third or fourth month the tiver b'^ina to take on this func- 
tion, wliicU is gradually lost by the placenta, Tlie constant 
prodnction of this principle in the econoiny, even in the 
early months of foetal life, is significant of the importance of 
its ftmction. 

The fanction of sugar and ita mode of disftppearance in 
the economy are not yet well undei-stood. Its early forma- 
tion in large quantity, when the prooesees of nutrition are 
mrmt active, si-ems to point to an important office in the 
performance of this geneiul function. Ita presence h iin* 
doulitedly necessary at all pcrioda of life; for its formation 
never ceases in heallli. Bernard has attempted to eliow that 
ita presence in the animal liiiids favors ceI]-development> but 
has lianiiy Buceeccled in establi&hiiig this fully.' 

It has been claimed that the sugars and fats are for the 
purpose of keeping up the animal temperature, and are 
oxidized or undergo combustion in the Inugs. Thie view 
waa afterwards modified by Liebig and others, who supposed 
that the oxidation takes place in the general pystein. This 
theory will be discusst'd more fully in the chapter on animtd 
heaL Here we L^an only Bay that, while tlioro are many cir- 
cumstancefi which, taken by theniaelves, might lead to such 
a conclusion, the production of heat in the body is closely 
connected with the general prticesa of nutrition, of which the 
disappearance of oxygen and fbi-niation of carhonic acid are 
-but a single one of many important changes. We have not yet 
fiufficient ground for the supposition that the substances under 
consideration are direetly and exclusively acted upon by oxy- 

'Bbbxakd, JJejonM de Ph^tinhgie ExpirimfTttale^ Faria, 180S, p, 247 rf ■'J. 




60 



IKTKODUCTHiN. 



gen in the yrganiem. Tlie tt-nii calorifit; element?, which 
is BO[iietIme.s applied to them, canimt therefore be accepted. 
When we endeavor to aubstitute for this theory a definite ex- 
planation oi' the ti?e& of PUgar in the economy, wft find our- 
selves at a JosB ; hut it must be rememl>ered that we are yet far 
from having a complete knowledge of the fauctions of the 
IkkI^j partii^ularly those connectfid i^ith the intimate pro- 
cesses of nutritiou. 

la the present state of science, we are only justitied in 
saying timt su^ar is important in the proi'ess of development 
and tmtntion, at all periods qf life. The jtrecise wurj in 
■wh'i-eh it infiuences ifiem pntoessea is notfuUij uiideraiood. 

Sugar dlaappeors from the hlood in its passage thronffh 
the lungs, ill great part, probahly, by conyereton into lactic 
acid. This chan^^ has been, demonstrated in the blood of a 
dlubetic patient ; till the sugar contained in the blood being 
thus chan^'cii in less than twenty minutes.' 

Sugar is never discharged froin the body in health, with 
the Btngle exception of the &ngar of milk in the female during 
lactation. Under certain diseased conditions of the system 
its production by the liver ia esagg'eratad, so that a certain 
quantity passes through the lungs, exists in the arterial blood, 
and appears in the urine, constituting the very serioua affec- 
tion called diabetes mellltua. 

Fatty or oily matters exist in both the animal and 
vegetable kingdoms. Those which are most intercating to 
us as physiologists are the varieties found in aniinahi, which 
constitute an important group of proximate principles. Both 
vegetable and animal tats are Lmpurtant elements of food. 

In tho animal economy fat exists in tliree varieties, which 
are called, reaiJectively, Oieinef Margarine^, and Stearine. 
In certain situations are fouud some of the fatty acids and 

Roots BUd TiAOUi, OMniu AnaUrmiqut, tome ii, p iai. 




FATS. ttl 

their combiiiationa, but they exist in minnte quantity, and 
their function is comparatively nniraportant. 

Composition and Properti^. — In their ultimate composi- 
tion, fats bear a certain resemblance to the sugars. Like 
them they are composed of carbon, hydrogen, and oxygen ; 
but tlie two latter elements do not exist, as in sugar, in the 
proportions to form water. From this difference wo should 
be led to suspect, what is really the fact, that the different 
varieties of fat are not mutually convertible. 

The fat which exists in the body is a mixture of the three 
varieties above mentioned, and is found in the ordinary adi- 
pose tissue, and in the substance of certain tissues in the 
fonn of minute globules or granules. It is not found in any 
great quantity in the blood, except after digestion of a full 
meal. It exists in the chyle in a state of extremely minute 
Bubdivision and suspension. It exists in the milk, also in a 
state of minute subdivision, but presenting some slight differ- 
ences from the ordinary fatty matter of the economy. 

Robin and Verdeil give, as the ultimate composition of 
Stearine, C„H„0,. The other varieties are separated from 
their union with each other with great difficulty, and have 
not yet been obtained in a state of sufficient purity for ulti- 
mate analysis. The reaction of all the varieties of fat is 
neutral. 

Fat, in greater or less quantity, is found in all the tissues 
of the body, with the exception of the substance of the bones, 
the teetli, and the elastic and inelastic fibrous tissue. It 
always consists of a mixture of the three varieties in varying 
proportions, but, with one or two exceptions, is never com- 
bined with any other of the proximate principles. In the 
adijjose tissue proper, it is enclosed in little cells which aro 
called the adipose vesicles. In all other situations it is in the 
form of microscopic globules or granules. As it is thus dis- 
tinct from other elements, it may be always recognized in the 
organism by the naked eye or the microscope. In the ner- 



62 



ISTEODrcnON. 



vouB matter thoi'p exists a pliosphorized fat, the compoBlttoii 
and properties of wbicli are not very W(4I undprstoud, in 
union witb organic matter. A minute quantity of fat exists 
in combication with tiie orjjtauic matter of the T^lood eorpn*- 
cles. 

Tlie fata are insoluble in water and Id the animal fiulde, 
ivith the ext-eption perhaps of tlie bite, whi^h Lo!fIs u small 
quaiJtitj in soIutioQ liy vii-tue of its enpuunceous coiiftituents. 
Tliipy are all very soluble in other nnJ hot uluohol, and but 
flllghtly soluble in cold alcohol. Tlie vfineties wliicli are solid 
at the temperature of tlie body, stearine and margarine, are 
easily dissolved by oleEne, which is liquid. 

The moBt marked distinction between the varietieB of fat 
is in their coosieteuce. Olelne is liquid at tlie teni[)erat«re 
of the body, and even at the freezing point of water, ilar- 
garine is liquid at or above the teni[*erature of 118°, and 
fiteariue al the ten^Krature of 143° Fiilir. The difl'erence in 
the couslstpofe of adipose tissue of different animals ilepends 
upon tbo relative proportion of the various kinds of fat. 



Saponification. — Wlien fat ia boiled for a certain time 
with an alkali^ in the prosenco of water, it undergoes a i>ecu- 
liai' decomposition which i% called saponification, A (Kirtion 
of the water is appropriated, and the fat is converted into 
gf^ceri-ne and uu acid. The acid 13 called oleic, Tnargaric^ 
or stearic acid, as it i& fonned from oleine, njarpariaej or 
Btearine. In this process the glyeerine remains uneoniliined, 
and the acid unites with the alkali to form what is commonly 
known as a aoap. 

Tliis kind of decomposition is called saponification bj a 
base; but tet-hiiically, saponification is regarded as any pro- 
eess by which a fat is decomposed into its acid and glycerine. 
Tliis may ho offeuted by pas&ing the- va])or of Avater through 
fat which has been raised to a temperature of 572° Fahr. The 
action of the strong acids is also to de(.'ompofie fat. "Wlien a 
fimall quantity of aeid is used, it unites with the f;lyeerlne; 



FATS. 63 

when a lai^ quantity is used, it unites with the fatty acid. 
The process of formation of glycerine and fatty acids in- 
volves the fixation of a certain quantity of water; so that 
the combined weights of the glycerine and acid exceed that 
of the fat originally employed.' It is thought by some that 
this acidification of fat takes place to a certain extent in di- 
gestion ; however this may be, it is not an essential part of 
the digestive process. 

Emulnon. — When liquid fat is violently shaken up with 
water, it is minutely subdivided, and an opaque milky mix- 
ture is the result. But this is momentary, the two liquids 
separating almost immediately from each other when they 
are no longer agitated. There are certain fluids, however, 
which have the property of holding fat permanently in a 
state of minute subdivision and suspension, forming what is 
called an emulsion. Out of the body, mucilaginous fluids 
and white of egg have this property. In tlie body, we find 
as examples of emulsions the chyle, which is fonned by the 
action of the pancreatic juice upon the fatty elements of 
food, and milk, which is composed of butter held in suspen- 
sion by the water and caseine. The property of forming 
emulsions with certain liquids is one of the most interesting 
attributes of the fats, as it is in this fonn only that it can 
find its way from the alimentary canal into the general 
system. 

Origin and FuncUons of Fat. — One source of fat in the 
economy is the food. It constitutes an important article of 
diet, existing in animal food in the frtrm of adipose tissue, 
and mingled to a certain extent with the muscular tissue. 
Vegetable oil also is quite a common article of food, ^\nien 
introduced in the form of adipose tissue, the lUt is freed from 
its vesicles by the action of the gastric juice, is generally 

' ItEGXAiTLT, Court £lhnentaire de Chimie, Paris, 1863, tome iv,, p. 414. 



64 



DfTBODCCriOH. 



melted at the teuiperature of tins baily, and float* in Oie form 
of oil on tlie alimentarj' mass. It pa&aes tliou into flje small 
inteelioea uuchanged, is emiikitied by the pancreatic juice, 
imd absorbed by the lacteals. A small quantity of lat is 
ab3orb<?d by the radicles of the portal veiu. After a fuU 
ineaJ, the lilood of a carnivomua anlmd frequently contains 
eisougb tatty ponileioii to form a tlik'k white peliule on cooUug, 

Tlie question as to the puesibilitj of the formation of fat 
in the organism may be now couaidered ag definitely settled. 
It haft been shown by Liebig, Boueeingault, and otbersj that 
ill young animals espeeialljj the fat in the body cannot all be 
accounted for by that which has been taken in as food added 
to that which the body contained at birth. The experiments 
of Boussingault,' on this point, on younji pigs, ate vei-y con- 
clusii'et and demonstrate that fat must be produced some- 
where in the organiam. Bemai'd* has shown that an emul- 
sive Bubetance, which he regards as fat in combination with 
organic nltrogenized matters, is produced by the liver, and 
Ib taken up by the blood of the hepatic vein. He believea 
that it IB produced at the expense of the amylaceous or sac- 
charine eleinentfl of food. 

It ia very certain that the generation or deposiiion of 
fat in the body may be influenced very considerably by 
diet, and the conditiou:^ of the eygtem. This is daily exem- 
plified in the inferior animals, and U true, though it is not 
perhaps as luiiiersal, in tbu human subject, It bos been 
found that a diet consisting largely of fatty, amylaceous, and 
Bnceharine principles favors the accumulation of fat, M-bile 
an exctnsively nitrogenized diet ia unfavorable to it, and \vill 
produce emaciation, if rigidly follo\ve(L Muscular activity, 
it is well known, is uiifjivorahle to the aet-nmulation of fat; 
which may account in a measure for its greater relative quan- 
tity in the female. In some individuals, especially when its ao 



' BoirsBin<ui:uT, CUimie Agrimie, Paris, litS*. 

* Okohabd, LtfOH* dt PhyriaUr^t Etj'iriirunlale, PorU, IBSS, p. 104 tt ng. 



FATS. 65 

cumulation is excessive, there is an hereditary tendency to fat. 
Organs which are in process of atrophy from disease, or other 
causes, are apt to be the seat of a deposit of fatty granules ; 
as the muscular fibres, which, in many diseases character- 
ized by rapid emaciation, are found to be the seat of fatty 
degeneration. 

There are certain situations where fat never exists, as in 
the eyelids and scrotum ; and others where it is always fonnd, 
even in extreme emaciation, as in the orbit and around the 
kidneys. Ordinarily, fat is pretty well distributed through- 
out the body, having a tendency to accumulate, however, 
beneath the skin, and in the omentum, where its presence is 
least likely to interfere with the function of parts, and where 
it serves to maintain the uniform temperature of the body, 
and particularly of the delicate abdominal organs. 

The average relative quantity of fat in the human body 
has been calculated by Burdach to be five parts per hundred. 
In the body of a man weighing 176 pounds, he found 8"8 
pounds of fat.' 

In certain parts fat has an important mechanical func- 
tion. It serves as a soft bed for delicate organs, as the eye 
and kidney. It is a bad conductor, and thus prevents the 
loss of heat by the organism. This is very important in 
some warm-blooded animals, ns the whale, in which the loss 
of heat would be very great were it not for the immensely 
thick layer of fat just beneath the skin. It is important in 
filling up the interstices between the muscles, bones, ves- 
sels, &c. 

Fat, like sugar, has undoubtedly an important office in 
connection with the general processes of development and nu- 
trition. We have not yet arrived at an accurate knowledge 
of the changes which it undergoes as it is used up by the 
economy ; for with the single exception of butter in the milk, 



* Bdrdacd, TraiU dt Phynologie, Paris, 1837, tome viiL, p. 60. Translated 
from the Qennan by Jourdao. 



66 iNTEODncnoN. 

it IB never diBcliarged ftom the body in health. We havo 
already alluded to the view that the sugars and fata are 
respiratory or calorific elements, which undergo oxidation 
in respiration, and are immediately concerned iu Che produc- 
tion of animal heat. One of the ai^raenta in favor of this 
lunction of fat has been that in cold climates, where tliere if 
a greater demand for the generation of heat by the Bjstem, 
fat is a more common and more abundant article of diet. 
This is undoubtedly true, but other principles are consnmed 
in greater quantity, and the general process of nutrition, of 
which the production of heat is but a single phenomenon, is 
intensified. . There is not sufficient ground for supposing that 
fat has any such exclusive function. Its oiBce is connected 
with the general process of nutrition ; and its vai-ions trans- 
formations in connection with this function, we have as jet 
been unable to follow. 

Fatty Acide and Soaps. — In addition to the fatty sub- 
stances jnst described, the following fatty acids, free, and 
united with bases to form soapa, have been found in the blood : 

Oleic Aaid (C„H„O.HO), 
Margaric Add (C„H„O.HO) 
Ol^aie of Soda, 
MargaraU of Soda. 

Oleic and margaric acids have been detected in minute 
quantities in a free state in the blood and bile. Their 
function is unknown. The oleate and margarate of soda are 
found in small quantity in the blood, bile, and lymph. They 
serve to hold in solution the small quantity of tJie fatty acids 
and fats which exists in these fluids. Tlie function of all 
these substances is com])arativcly unimportant. In the blood 
of the ox, Robin and Verdeil have found a small quantity of 
stearic acid and the stearate of soda. 

Odorous PrinGi^£e. — It is well known that the perspir* 



ODOBOUB FBINCIPLE8. 67 

tion of certain parts, as the axilla and sometimes the feet, hoa 
B distinct odor. This is supposed to be due to combinations 
of volatile fatty acids with soda and potassa. Most of the 
inferior animals have a distinctive odor, which may generally 
he readily recognized, and is always strongly developed in 
the blood by the addition of sulphuric acid. Barreul gives 
the following conclusions as the result of an extended series 
of observations on this subject : 

" 1. That the blood of every species of animal contains 
a principle peculiar to each one. 2. This principle, which 
is very volatile, has an odor like that of the perspiration. 

3. The volatile principle is in a state of combination in the 
blood, and while this combination exists it is not ap])reciable. 

4. When this combination is destroyed, the principle of the 
blood becomes volatile, and from that time it is not only 
possible, but very easy to recognize the animal to which it 
belongs. 5. In each species of animal the odorous principle 
is manifested with greater intensity in the male than in the 
female. 6. The combination of this odorous principle is in 
a state of solution in the blood which permits it to be devel- 
oped either in the blood entire, in the deiibrinated blood, or 
in the serum. 7. Of all the means employed for setting free 
the odorous principle of the blood, concentrated sulphuric 
acid is that which succeeds the best. It suffices to add one- 
third or one-half of the volume of blood employedj and a few 
droi» of blood is sufficient." ' 

Lactic Add — Pneumic Acid — Pneumaie of Soda. 

Lactic acid may be formed by what is called the lactic acid 
fermentation of sugars, particularly sugar of milk. Tiiis kind 
of action is induced by the presence of certain orgnnic fer- 
ments, or by organic nitrogenized matter in process of de- 
composition. This principle does not exist, as was at one 

' RoBUi anJ Vkkdiel, op. fit., tome iii., p. 90. 



IKTEODCCnON. 



time BuppoeeiT, in fresb milt,, but oclj afVor it has become 
Bour, Itfl composition (C,H,0, 4- 110} asshuilatefl it to tLe 
BUgtirs, Hnd indicates Low it may be formed theoreticully from 
tlieui hy trauspoaition of tlifir utoms ; milk-sugar liaving for 
ita compoeitioD C„II„0|„ which is also the formula iur aii- 
liydrous glucoae. 

It ia a constant constituent of the gastric juice, and ia 
indispeusuble to the digestive properties of this eecretion. 

Lactic acid lias been demouetrated by Liebig in tlie 
joics of muscular tissue,' 

Sources and Inunction. — This principle may be fonned, in 
miiiuto quantity, in the iutestineSj from tlie saccharine and 
amylaBeoua articles of food ; but it is in greatest part pro- 
duced in tlie economy as an element of eecretion. It is 
thought tlint a great portion of the sugar which passes in the 
blood from the liver to the Inngs is converted into lacticacid. 
If this be the case, it unites with bases and is almoet imme- 
diately decomposed and lost. Lactates in tlie blood are very 
readily converted into c-arboiiatca, as has been shown bv the- 
exppnraotita of LehmJiiin,* who took into the stomach half an 
ounce of dry lactate of soda, imd in thirteen minutes his 
urine had an alkaline reaction trom the presence of carlMin- 
ates. Alkalinity of the urine from thiK cause is otl:en pro- 
duced byrhe ingestion of comhinatiuna of the vegetable acids 
in fruits, etc. 

The moat marked function of lactic acid is in the gastric 
juice, and wilt he considered under the head of digestion, 

±*neiimiG Aoid and PneumaU; of Soda. — Pueumic acid 
was discovered and cxtmcted from the tiesno of the lungs by 
Verdcil in 1S51.' Its ultimate composition la not given. 
According to thid author, It exists in tlie lunga of the mam 

' Lehiun!(, Fhyntto^al Chmivtry, Fhiladclpbk, 1650, toI l» p. M. 

* niiiil p. -07. 

* fl'jatN Olid Vedjiiue, oji. elL. tome II, p. 4il4. 



OBOANIO PRINC»>LES. €9 

malia at all periods of life. He extracted about tliree-foTirtlia 
of a grain from the perfectly healthy lungs of a female who 
was guillotined. It has not been found in other Bituiitiona 

Its function is connected with respiration. The carbon- 
ates and bicarbonates of the blood, in passing through the 
lungs, are in part decomposed by pneumic acid, a certain 
portion of the carbonic acid in the expired air being evolved 
in this way. 

PneuTfiate of Soda is produced by the action of pneumic 
acid upon the carbonates of soda in the blood, and is found 
in the blood which passes through the lungs. It is not dis- 
charged from the body, undei^oing in the system some 
transformation with which we are unacquainted. 

OEGASIO NTTEOOENIZED PRINCIPLES. 

Principles of this class differ essentially from all the other 
constituents of the body. They are the only elements en- 
dowed with what are called vital properties, and upon them 
depend all the phenomena which characterize living struc- 
tores. This important fact cannot be too fully insisted upon. 

All the 80-caMed vital phenmnena which taJce place in the 
hody depend primarilij upon organic niirogeniztd pHnciples^ 
which are the only elements in the organi»m endoxved with life. 

By a tissue or fluid endowed with life is meant : 

A combination of proximate principles which hactheprop- 
erti/, wider certain conditionSj of aj^opriating materiaUfw 
its nourishment and regenerating itself to repair the continual 
destruction or waste to which all living bodies are subject. 

This, which is the great process of NuiRmoK, is going 
on from the beginning to the end of life ; its phenomena 
are distinct from those which take place in inert com- 
pounds, and ai-e called vital. Tate, for example, the nutri- 
tive processes which take place in the muscles or the bones. 
In common with all parts of the body, these tissues are 
continually undergoing waste. The circumstances under 



ro 



ETTEODCCnOIir. 



wiiicli tliej can eupplj this wa&t^, or regenerate tbeniBelrm hy 
the approj>riation of snitaLle iiinterials^ involve eontaftt with 
the circulating blood. TLcy take materials fromtbis fluid and 
change them into their own substance. This procea; taki-a 
place oalj' in living bodies^ anrl is unknown in the inorganic 
ksngdotn. Afi it id t!io great characioris-tic of life, its atcom- 
plighmept being the enJ and object of all the functions of 
the organisiUj the study of these organic principles is mnni- 
festJv of the greatest importanee. We shall find that their 
properties are pecnliar to theinselree, and their ebeoiien] st^idj 
must necessarily be eminently ■jihytndofjical. To arrivo at 
any definite idea of their properties, the methods of study 
which have been generally employed by chemists must be 
discarded, as by these they are reduced to inorganic ele- 
ments, and treated dmply aa combinationa of inert sub- 
stances. They must be studied as nearly as possible in the 
condition in wliich they exist in the bwly ; which ie nece&- 
earily the conditiun in whlt-h they are capable of tnanifestlng 
tbeir characteristic vital pbeuonietift. 

Thei^e principles are found iit all the fluids, &en;ieolida, 
and sttlida of the body, except the excrGmentitious fluids.' 
The nutritive fluids contain several. In each tissue an or- 
l^auic jirincipie is found which presents certain peculiarities 
morti or lesa dieriuctive. They are all funned in the or- 
ganism, and, with the exception of the milk, a little mucus, 
desf]uamflte<l epidermis and epithelium, and an abnoat inap- 
prec-iiibie quantity exhaled by the lungs and skin, are never 
discharged unchaflged ^om the Ijody, in health. They 
assume the coneistenee of the part in '"■bich tliey ai'O found ; 
Wing,, tlierefore, fluid, somieolid, and solid. They constitute 
by far the greater part of the organism ; but their cjunjitity 
in tiie whole body has never been accurately estimated. 
Their reaction is neutraL Ab a peculiarity of chemical coni- 
poBition, they all contain nitrogen ; whence they arc wdled 

* The escriRQont!tiou9 fluids conLkiD roloriog mBteprs, vhicli nobin knil TordoU 
put In tliEfl clasi, liut wbLcb do nut accm u Ut endowod wiiJ] -riul pTopcniM. 



OBOANIO PBCfCIFLEfi. 71 

Xf^Urogenized J^rindples. They all closely resemble one of 
the most important and certainly the most carefully studied 
of their number, namely, albumen ; whence they are some- 
times called Alhuminoids. They were regarded by Mulder 
as compounds of a tlieoretical radical or base which he 
called ProUine^ and alter tliis chemist are sometimes called 
Protelne compounds. 

Composition, and Properties. — 1. Studied, as. they gener- 
ally have been, from a purely chemical point of view, tliey 
are regarded by many aa solid substances in soliltion in the 
fluids, in a condition approximating to this in the semisolids, 
and of course as solid in the solids, like the bones and teeth. 
This view is erroneous, as we shall see that some are natu- 
rally fluid, some are semisolid, and some are solid. In this 
condition they have been found to consist of Carbon, Hydro- 
gen, Oxygen, Nitrogen, with sometimes a little Sulphur and 
Phosphorus. The coloring matters contain in addition a 
small proportion of Iron. By ultimate analysis they have been 
found to be of indefinite cJiemical composition* which, indeed, 
we would be led to expect from the state of continual cliange 
in which they exist in the body. By the method em- 
ployed in arriving at their ultimate composition, even before 
analysis, they are completely destroyed as organic principles 
by desiccation, and rendered incapable of exhibiting any of 
their characteristic properties. The composition of their 
dry residue only is tJiua given, while in reality tlicy all con- 
tain more or less water, which enters into their composition, 
and deprived of which they caimot be called organic sub- 
stances. The proportion of water ia to some extent variable, 
but confined within tolerably narrow limits." 

2. The organic principles never exist alone, but always in 

' SoBin and Vehdeil, op. nt., tome iii., p. 147. 

■ For a farther discuasiun of tliia important subject, see an article by the author 
m the Ameriean J<mmal of the Medical ScUnca, October, 1883, On Vu OrganU 
yUroffenUed Principln of the Sodi/, teUh a New Jfethod for their Ettimatitm in 
AeNood. 



72 



INTEODUCnON. 



be ,1 



cotnLinatlon with inorganic sulBtanceB, wliidi, though per- 
haps not ttljsolntelj necessary to tbe properties by liTliieh they 
are recognized out of the bodj, are essential in the perform- 
anee of their vital tiinctions in the economy. Under these cir*^H 
eumatances the organic and inorganic priueiples are so elo&ely ■■ 
UJiitetl, that the latter may be said to acquire, by virhic of 
this uniou, vital properties. Though unaltered, the inorganic 
arc discharged -n-ith the worn-oat organic substances, and, 
combined with fresh organic matter, are deposited in the 
tieeues in the process of regeneration. 

3. The organic principles which are natnrally fluid maj 
be coagulated, but under no cirL'unistanL'efl do they assume a 
definite or crystalline form. We ehouhl be led to expet^t this 
from the ffict that they have no absolntely fised compo^ilion. 
When tho liquids of this class are thus soliditied, tbcy are 
Jiot precipitated from & solution, but are made to assume 
a new form, stiU retaining their water of composition. 
"When exposed to evaporation, whetlier they he fluid or scmi- 
Bolid, their water may be driven off, and they are said to be 
demccated. They can be made to assume their water of 
composition again by simple contact, aa thoy have in n high 
degree the property n'l hjffrometricity. Both these properties 
are pet-nliar to organii: substancea. 

4. Wlien exposed to a very elevated tetnperature, that 
which hoa been considered by chemists as the organic sub- 
Btance proper is volatilized and driven off, leaving the inor* 
ganic substances, whic-h always enter into Its composition. 

5. In their natttral condition, the ot^atitc prlaeiplea have 
no very distinct odor ; but when exposed for some time to a 
moderate beat, certain odorous or emjiyrcumatic eabstancGS 
are produced, Tliia change is peculiar to oigaoie matters, 
anil takes place in the process of cooking. "When these ele- 
ments are nsed as food, this process serves a useful purpose, 
rendering them more agreeable to tbe teste, and facilitating 
tlieir digestion, 

G. One of the great distfnctive properticfl of organic prio- 




OBGASIO rEDJCIPLES. 



78 



oiplos, out of the body, is pvtr^'actwn, Tn contact ■witb 
the aip, at n muclt'rare teniperatiire, tliey undergo ctecomp<v 
eition into carbonic, laetk-, itmJ butyric acids, and ninmouia. 
When this change has once t-otnmericed, it has licen found 
by Wurtz to continue m a vacuum/ Putrefattioa ja a 
process j^>«culiar to organic substances. By it tbcy are 
trftusfonijed luto subetances which are used in the nutrition 
of vegetables ; and as Tegetitblcs are eventually consumed by 
BcimaU, the animal matter is nut lo&t, but returns again 
throngii this channel, so that the two kingdoms are continu- 
ally intcrchaugiiig elements. Organic matters in putrefac- 
tion are capable of setting up the same procpsa in other 
articles of this claea by simple contact, neither giving up nor 
taking away any chemical eleraenta. TLry are then called 
jWmi-ntu^ and tliis action is said to be catalytic. As l>cfore 
remarked, this constitutes one of tbe most important charac- 
terisiica of organic mattei's ; one, indeeil, which enables na 
to recognize them when they exiat in qiiautitiea too minute for 
dieinical analyBis, as in exhalations ti'oiu the pulmonary and 
cutaneous surfaces, 

Proteine. — In 1838, just after the publieatiim of the 
theory of Testable organic radicals by Liobig and Dumas, 
Mnlder attempted to show that the organic animal substan- 
ce* Ti'ere all compounds of a radical which lie called Pr^t^- 
iW. TJii& tiieory was pretty generally receivedj and gave to 
organic inattere the name of Proiehie Compounds, by wliieli 
they are sonietimes known, lie treated allninieiR, fibrin, and 
caseiue with alcohol and ether to remove the fats, and with 
hydroL'hloric acid to remove inorganic salts ; dissolved them, 
thus pui'ifiedj in a Bolution of potflflli^ and jirecipitated ivith 
iieetle acid a substonce said to possesB always the same char- 
acters, which he called proteine ;, and which, by union with a 
certain quantity of sulphur and phosphorus, was capable 
of fonuing iJbmi, albumen, and caaeine. But the finalrses 

' t^ted bj BoBiN nnii Vkudcil, op. cit., tome iii., |). Hii. 



n 



IHTBODUCriOH". 



of diftbrent cbemiste have shown that protcitie itself liOfl nn 
indefinite cbemi(;al compoaition, lianily any twn turmuljE 
being the same. It is essentmlly (in artificial prodaet; mid 
with the views we Lave taken of the coRipoe-ition of ori^nnlc 
substances, there is not the eligUtc&t reason to snppose thiit 
it plnj's tlie part nf a. base or radical for a group of d«fiiiito 
compoTintis. It ia not a diatiiift cbfmipal siibBtance, for 
its coiupoeition is iudefinite ; nor a proximate principle, for it 
ia prodnced artificially and by decomposition. We mnet 
therefore reject tbe theorj' that it senes ns the rndiL'al of a 
definite series, and dUcard the name of Proteiue Compounds* 
as applied to organic pHticiples. 

Catahjsi^, — Catalyfiis, or cntaJytin action, is a name given 
to a certain profcsa wliidi we do not as yet understand. The 
word was introduced by BerzeliuB in 1835, and applied to 
certain actions or affinities brout^'fit into play in inorwanie 
bodies by the mere presence of another substance, the latter 
not imdergoing any cliemical alteration. It is now appliec! 
to all chemical charges which are induced by the ginipie 
prejietice of any substance, like the particular class of sub- 
gtniicee called ferments, in which the subatance inducing this 
action undergoes no chemical change. Fermentation, irhich 
was considered in treating of sugar, is an example of catalysis ; 
the sugar being decomposed into carbonic acid and aleoliol from 
the fact of the mere presence of yeast, whicb has nothing t-o 
do, c/tcmiealli/, with the process. Putrefaction, which we 
have just considered, is an example of catalysia; for a small 
quantity of any antinal substance in a state of pntrefactiou 
16 capable, ht/ if^ pre«a}-c€j of Betting Up the same procees in 
other principles of this class. Kntrition, and to a CBrtain ex* 
tent digestion, are examples of catalveis; for ia the repair 
of the systooa, certain materials are taken from the blood by 
the tissues, and by the latter cbonged into diiFeront Bub^ 
stancefi, as inuaeuline for the muscles, oeleino for the bon^ 
etc.; and iu digestion, the organic elemcute which are dissolved 




OBQANIO PRINCIPLES. 76 

are changed bj the presence of certain oi^anic eubstancea m 
the digestive fluids. Any process set up by the mere presence 
of BubstaneeB, whicli themselves undergo no clietnical change, 
or the transformation of one variety of organic matter into 
another from the mere fact of contact, is called catalysis. 

The general properties we have mentioned are possessed 
by all organic principles ; which, indeed, difler from each other 
very httle in their general characters, and even in ultimate 
composition. Those which go to form the tissues are endowed 
with identical vital properties. Robin and Verdeil give seven- 
teen distinct substances belonging to this class, of which four 
are coloring matters.' But three of these principles have been 
carefully studied with reference to their ultimate composition ; 
but their composition, which is indefinite, and not necessar}' 
to their vital properties, is of little physiological interest. 
The number of equivalents of the various ultimate elements 
is entirely arbitrary, as these principles enter into no definite 
combinations. 

Table of Organic PAncipUs. 

Sam4. Whtr« Found. 

' Plasmine (decomposing into fibrin and iTiCtal- ) i rh I I ■ h 

bumeii) \ ' ' ' ■ 

I Hiood, CIitIc, Lymph. 

Albumen and senne -i „ '■,..„ 

t Serosiiici", Milk. 

Albuminose Chjiue, Blood. 

Calcine Milk. 

Mucocinc Hucua. 

Pancreatine «... .Panereatic Juice. 

Pepfin Gastric Jiiit,-!'. 

■ Globuline Blood-Globulos. 

MuHcaline Muscles. 

Osteine , . .Hone. 

Cartilagine Cartilage. 

Elasticinu Elastic Tissiio. 

Ecraline N;iils, Iliiir, Kiiiilcrmis. 

CrvstalUne CrvstiiUinc Loii:'. 



4 



<£ 



s 
■g 



' Theaq authors do not consiik>r that pepsin Iihh been fully ciilabli.ihcd as a 
distinct proximate principle. Its distinctive properties socra to be sulfieientlj 
well marked, and it has therefore been included in the liat. 



76 



INTDODUCTION. 



yam* 
' HicuMj^IobinG .. . 

Mi'lanlncj 

Bilivordine 

ITrrosauine, ., .., 



All cont&ta iron. 



Coloring U&cter of IlIootK 
" " PLgnienl. 

" " Hilt 

Uiioe. 



Plagmine (demmpcmnf^ Into Fibrin and MetaHmifm). 

tTndcr cert4iin nlinonnal conditions in the or^mism, or 
■when tlrnwn from tlievcssols, the blood, Ijnipb, and rhyle will 
spontauecmslj coagulate. It is thought thrit this coafiulatiou 
IS due to » decoinjioiiitidn of a proximate pnuefplc, called 
plaeinine, into fibrin, the coa^dathig eubstanw, and metal- 
bumun, which renmiQ& liquid. It is certain, liowever, that 
when the blood coagulates, a substance called tibriii makes 
its appearance in a semis^ilid form ; and it is important to 
study this principle, whe'ther we ret'uj^ize it as a normal 
constituent of the blood or us a product of decomposition. 
This question ■wilt be fulty considered in connection with 
the composition of the blood. 

The proportion of moist fibrin which may be cjttwicted 
from tiie Wnod is between eight find nine parts per thou&and. 
This proportion is nadoubtedly quite variable willun the 
limits of health. According to Becquerel and Kodier,^ itfi 
quantity is considerably increased during geetatloii, and is 
greater in iidultd than in very yonug or ver\- old jiersons. 
As a general rule^ it is more abundant in Hrteriul than in 
renons blood, and is often entirely absent from the blood 
of the hepatic and renal veins. Xo constant dit!'crence ia 
quantity has been established in the eexea, and its propor- 
tion appears to buar no definite relation to the vigor of the 
rndividual. 

The best process for the oxtractiim of fibrin is to whip 
the fluid, freshly-drawn, with a bundle of twigs or broom- 
corn. In this wiiy the fibrin may be quickly and completely 
Boparated. It i& then free<l from foreign matters, such as 

' HlCi'gtlli.K]. rr Rnnmti, TVadt Jr rKiaiu patMogigtu^ appli^utt d fa mideritti 
ftrntiijuf, riirin. ISIH, p. 10], W*^, 



OBaunc PECTCIPLES. 



blood-corpuscle*, by wnetinf,' under & streiim of water, at tho 
some time kueaJiiig with tbe liugers, 

Properties of Fibrin. — The striking pcouHarity by wliteh 
fibrin is rocugnizeJ is its spontaneous coagulability. All tlie 
fluids in whicii it is fonned, iivbi;n diawo iVym tbe body or 
placed under abnormal conditions, becoiiie more or less 
congvilated, and their coagulating prineljilc Is called fibrin. 
It is Ibis substant'e, tlierefore, wliicli ^ives to tlie binod its 
{lUGuHar and important property of coagulability. The con- 
dition nndpr wliicli fibrin coagulates seems to be that of stasis. 
Whenever blood is drawn from the body, or in tlie veasols, 
wheu circulation becomes lurceiedt it asBumes, atter a variable 
time, a seiuiaolid consistence. The eansc of this rem;irl;able 
plieiicfnenou \& ft quGstlou of gi'Gat interest and one 'rt'hicb 
hflB long engaged tlie attention of pbyiiiologistfi. This will 
be fully couaidered in connectiou with the composition Slid 
propertioa of the blood. 

I'ibriu does not coagulate into a liomofi^crteoHS mass, but 
forma minute, mieroflwipic tilanicnts, or fihrila, uiiicli after- 
ward contract fur ten or twelve huiirs, so that the cL't at 
the end of that time is much fiuialler than immeiltately after 
coagulation, 

\vi recof^iize as tibrin that organic principle which 
coHgulatL-a whenever the blood, lytnpb, <.n' cbyle, i$ rynioved 
from its nfltm-al condition. By coagulation, its form only is 
cbauged, not its weight, and wo must consider, therefore, 
the water which is contained in the coaguliited mass as unter 
of compoc^iticm. 

Pure eoiigulftted fibrin is a grayipb-whito substance, com- 
posed of micrnscopie fibrils, and posseBsiug considerable 
strength and elasticity. It is ijisoluhlo in water and in the 
serum of the blf>£»l, bnt dissolves slowly in eolutions of caustic 
alkalies. It swells, assume* ft jelly-like consist oticc, and i$ 
finally piirtially dlasohed in. a very feeble mt.xture of hydro- 
chloric acid and water, Lite all organic nitrogcnized sub- 



TS 



INTEODUCnOir. 



Btaiiccs, it decompoBes nt a moderate temperature in contdOt 
witli the air nnd moisture. 

In the first edition of this vohime, ■which wns publUlied 
in 1S60, wc treated uf fibrin ae a proximate principle, ns- 
swming that its separation iVoui the liquids of the body that 
are epontaneouGlj coagulable wna fiiinjilj a chan^ in tlinn 
iVora liquid to semisolid. We tliea adopted the theory that 
coagulation of the blood ia preveuted by the presence of a 
priricijilo capable of maintaining fibrin in its naturally litpiid 
condition. As we shall see wheu we come to discuss the 
cause of the remarkable phenomenon of coagulatiun of the 
blood, there are many substances which maybe added to ihe 
blood fttler it has been drawn from the vessels and which 
v:i\\ prevent its coagidation ; but it has not been pitBitivuly 
demonstrated that the circulating blood contains normally 
a volatile' siibBtanco, the exhalation of which is the cau&e of 
coFiguliUion. In one of the steps of the process lor the ex- 
traction of plasmiue from the blood, coagulation is prevented 
by the addition of enlphate of soda. This enables lis to 
Beparate the plasma from the corpueclea. The pla^mine, 
tbuB kept in a liquid state by sulphate of soda, ia precipi- 
tated or coagulated by an excess of chloride of eodimn, 
having nndergoue no decomposition ; but this coagulated 
plaeinlne may be dissolved in wnterj when it decomposea 
Epontaneouely, and two new fiiibstaiiccfi, fibrin and nictal- 
bumen, maho their appearance, those jhrineiples not being 
recognizable in the normal cireulatiug fluid. It is furthia 
reason that we no longer recognize fibrin as a proximate 
principle, regarding It, rather^ aa a product of decomposition. 

Organisation of Fthnn. — ^The question of the organisftc^B 
tion of accidentally effused find coagidnted fibrin has occupied 
the attention of patholngists a groat deal, and some are of 
opinion that it is cap.ible of becoming part of tho organized 
living structure. This supposition- had its origin in an 
snmed identity between fibrin and reparative lymph, org 




obOa^c i'mssciPL^&. 



n 



as it is sometimes caUetl, coagultible Ijmpli, which repairs loesea 
of tissue. As the process of repair of parts after destruction 
must be considered aa analogous to, and almost identical witb, 
ordinary nutrition, the above question, whinh is bo important 
in ]>fLtbalogy, is one of gi-eat physiological intereat. 

Tlie conditions undei' which the organization of 6hrin haa 
been a^umed to have taken place, are in elota remaining 
after vascular eitraTaaalicms, and fibnnoue exudations upon 
inflamed aarfacL-s. Tho most impuitant information is to be 
derived from a Btudj of the anatomical characterB of &uch 
efliisions. By the microscope, and all means of inveetigation 
which arn at our command, it ia impossible to dtstin^iish in 
these effnsiona any thing but fibrin. There are no bloud- 
veaaels, nei-ves, nor any anatomical elements wliich would 
lead «B to etippoBC them capable of self-regeneration, that 
distinotive property of all organized tissues; and, in addi- 
tion, th^e are never developed. The changes which those 
eSiisions undergo are retrograde in their charaeter; »nd the 
fibrin, if it be not ahaorbed, remains as a loroign eubi^tance. 
Tlie fibrillatiomvhich takes place is "by no means an eridenee 
of even commencing organization; for in etfueious into the 
tiesues it soon disappears, and if the effusion be not too large, 
tlie mass breaks down and is finally absorbed. When, on 
the other hand, effusion of organizahle lymph takes place, 
Ihe process ia very difl'erent. It is elaborated, indecd^ rather 
than effused ; first appearing as n homogeneona fluid, in 
which fibro-plaet.cc nuckf, then fibres, are developed, and in 
some instances blood -veseeln, lymphatics, and nerves. Ac' 
cording to Robin, plastic lymph does not even contain fibrin ; ' 
much IeS3 are llie two identical. The process of organization 
is slow and gradual, and in no case does it take place from 
the blood, or elements of the blood, suddenly or accidentally 
effoeed. 

There can be no doubt that effused and coagulated 

' LiTici Et RoBiy, Dict'ifwair* lit miirfiin', Pnda, laia; Article, Lympke, 




80 



y^uc 



fibrin IB itu-a]mb]e of orgnnization ; and U may be farther 
statptl, as ft general law, tliat no eiiifjle prnxiniate priiiflple, 
or ifiere mccbanical mixture of prosimatc jirmcijik-s, effiined 
into any part of the body^ ever acts in any other way than 
B3 H foreign Bubstance. 

In oc-itftin inatauees of morbid action, efl'u^ioiis tato place, 
eitber on the sTirfacefi of membranesj or between two oi> 
]>osing surfaces, attaching tlieiii to eath ether by bridlce or 
adhesions, whin-li actually btrcoiue orgariizeii. This ow'urs 
most frequently in eerous nienibmne^, and the structure tJius 
formed is entirely different from coa^ilated fibrin, whieb has 
no connection with Llie parts, except that of contignity. Both 
of these formations have been included in the term false 
membranes ; but Robin makes a verj' proper distinction be- 
tween tliem, ealling the one, which is merely cofigitlated 
fibrin, like the membrane of croup, falie membranes, or 
paeudo-membranes, and the others, membranes of new for- 
laotiou, or neo-iuembranea. The fumier consist simply of 
the fibrin, wliieh Xuture has been unable to remove by ab- 
Borption ; mid the latter, of rcgniarly-elaborated anatomical 
eleiuentB, endowed with the properties of Botl- regeneration 
common to all organized etructiireB. 

It is thotigbt by some writers, as wg have already stated, 
that fibrin ba^ its origin in a sjiODtaneous decomp'i'i'itii.in of 
plaginine, tlie two finhstaut'CB furmed being tihrin and metal- 
bumen. Others do not accept thia Bimi>te view, and regard 
fibrin as the result of the union of two subetant-es which 
they call tibrin-facforB, nr fibrinoplasliti and lilirinogenic 
matter. Still another view is that these two eo-callcii tiiirin- 
factors may GNiwt in the blood, hut that their nninn to form 
fibrin can only take place in the presence of a peculiar fer- 
ment. These i^nesttons will nattirally be considered in con- 
nection with the $id>jei.'t of coagidation of the blood, which 
IS etill somcMdiat obscure. At present, we shall confine oiir- 
bcItcs to what eeeme to he the most imi>ortant fuiicftion of 
fibrin. 



ORGAHIO PRraCTPLES. 



81 



As we sliall see farther on, the co«gu]al>tHty of tlie blood 
is spLcially important in the &pontniiDuus ftrrcfit of Ln-iuor- 
rliitge ftfter divisitm oi- rupture of sinnll vessels. In certain 
ca^es of wliat h known as the luemonlifigic diathesU, in 
wljieh eevero litemorrhage occurs fuliowiog' very sligbt 
Wounds, the blood has no tendency to eoagulate, uud, for 
fiomc reaaon, fibrin is not formed. Tlio^e cases do not ncceEr- 
sarily present any disorders in general nntriticn, and the 
peculiar condition of thu blood beeomes ap}»arent only when 
vesecls are divide*!. It is a curious fact, also, that defibrin- 
ateil blood will regain its coacjulsbtlity after it lias passed 
tbrongh the tisM^ues, as has been Bliown by injecting de- 
fibrinfltod blood into the nrteriea of a criminal just after 
death. In this experiment, performed by BroT^n-Sequnrd, 
the blood returned by the veins coagulated and presented 
a notable quantity of tibrin.' 

It has long eince been noted that tlio hlood of the hepatic 
and renal veinB will not coagulate, and writers have spoken 
of the blood of these veesels aa contiiintng no tibrin ; bnt 
physiologists have not been able to ascertain any thing more 
than this simpie fact, and ive arc not acquainted with tho 
changes which plasmine unflcrgoes in the pasBage of tha 
blood through the liver and kidneys. 



Alhvm^m and Senne. 

Albumen or eeritie is found in the blood, lymph, chyle, 
intemiuecular fluiti. eecretiona of fieroue membranes, and in 
aniall qunutity in the milk. Serine exists in considerable 
quantity in the blood, constituting an important organic 
constituent of tho plaeraa. In some analyses designed to 
give the qiinntily of moist albnmeu (serine and mctalbu- 
men) in the blood, wc have found a proportion, in a healthy 
Bpecimen, of 329-32 parts per 1000. The proportion will 

' Olcd bj Kosifl IT VsKPKt, CSufiiV anaiomi'gw, Piir3s,_lB03, tdme ill., 
p. 2«ft. 



82 



rNTBODUCnON. 



undoulitedly be found to vary considerably witliin the Hniite 
of Iiealtli, and, aa a rule, it Ijesirs an invei-fie ratio to tlie quan- 
tity of fibrin. No confltant diflcreuM iu the quantity of 
albnmen in tiie sexes has heen establislied. The qUBTitity la 
greftter in the weU-nouri&hed and vigorous, than in anremic 
and feeble biibjects. 

Albumen is found in the orgaiugm at all jieHoda of life, 
existing even in the ovoni. 

In nltimat* composition atbonieu Las heen found by 
chemists to differ very little, if at all, from filjnu. Like the 
other principlee of tliJe olass, the proportions of its ultimate 
elements are indefinite'. 

Albumen may lie estrautnd from the fluids in wliieb it is 
contained by simple congnlation. The luoet convenient 
raetbod of eepjirating it is to add to the liquid a quantity of 
absolute alcohol, and immedlntely filter. In operating upon 
the scrnm, we liave found that about twice its volume of al- 
cohol will coa^ilate all the fllbnmeu (serine and metalbumen). 
It may then be collected on a filter, and its weight will rep- 
resent (be proportion of ttila principle in its natural condition. 

Serine and iiietalbumen, wbidi were formerly regarded 
aa Alb;uuQa of the blood, will be fully doseribod in cOunec- 
ttun with the chemistry of the circuhtting fluid. 

jpropefii^s &f ATb'umen., — Liquid allmmen has certain 
properties whlcli serve to distinguish it iroiu other principles 
of tlie same class. In a neutral xoixture it Is coagulated com- 
pletely by a temperature of 16T^ FflhT. The same result fol- 
lows the additionoftJiBfitrong mineral acids, alcohol, and some 
of the metallic traits. It m distinguiehed from caseine by 
the fact that it ia not coagulated by the vegetable acida. 
Coagulated albumen isagrayish-whitoBubBtance, ahvaya com- 
bined with inorganic matter, which pannot be separated with- 
out incineration, insoluble in water, but Bolnble in a weak soln- 
tionof acaueticalkali. In an alkaline solution it is no longer 
congulahle by heat. Becquercl has found that albumen haM 



OEOANnO PEEHCTPLES. 



83 



le property of deviating the plane of polarization to tlie 
Itfft. He has employed it polariziug apparatus Jikt- the one 
used by Biot in tine esaraination for eugar, for the purpose 
of estimating tho qnautity of allmmen in a watery mixture, 
aiid ftmiid that '" eath mi-iTito of deviation corresponde to 
IS deei^ariiraes (29'77 grains) of dried albomen in IfiOO 
cubic ceniiinetres (l'7f> pints) of water." ' Tliiti instrnment Le 
culls aa alhuminimet^r. A current of galvanism passed 
throTigih a mixture containing albumen pi-orlncea congiilation^ 
which has been attributed to a denom position of certain aalts 
which are combined with It and maintain its fluidity. 

Borne organic princtpleg almost identical with albmueti 
in chemical reactiofls^ are found to possess very different 
physiological properties. One of these is the organic prin- 
ciple of the giietrie juice, which, like albumen, is cuagidable 
by heat, alcohol, and the metallic ealfs, but exerts a pecnliar 

id distinctive action In the dige&tion of curtain articles 

' food. 

Tests Jbr AHmmeji. — As a patholopcal condition, alhu- 
men soinetimes exists in the Tirine, and it becomes importrint 
ch'nit'ally to be able to determine th!3 fact by the application 
of t£tite. These require certain precautions for their suc- 
<^eBsfitl application. They depend upou its property of 
coag^ulation. 

If a solution containing albumen be exposed to heat 
ia a teet-tube, ae the temperature rises a plight tdondinesa 
or opacity in the upper part of the liquid occurs, which 
pradimlly extends tlirougli the whole mass, aintil, at a 
temperntnre of ahout 16"'^, a precipitate more or less abun- 
dant ia jiroduecd, which is entirely insoluble. If albumen be 
very abundant, the whole nines may become Bolidified, and 
we nmy have all fihades between this and the slight opacity 
prodneed by a very minute quantity. In tlie latter case 

E»«arei«t And EooiEB, Traite de Chinae Pa^loffi^ut^ ParU, 1B84, p. 08. 



34 



DTTHODrcnOS, 



coagulation is not complete until tlie liquid lias been, broagbt 
t» tLe boiling point. It must be tomemberod. however, tbat 
albumen is not coa^Iated by heat in &n atkalloe eolution. 
lu teetlng tbe uriiio Ibr albunieii by li eat, if tlie liquii) be 
alkali tie it mu&t benentralizeJ witb a little acetic acid; other- 
wise there will be no coagulation, even if albamen bo preecnt 
in abnndance. There mny also arise a sourt^e of error from 
tbe pre*.'i[ntation by heat of an esoe&s of earthy phosphates. 
This precipitate is diatinguiehod froin albumen by the fact 
that it i^ dissolved by a few tlrop-s of hydrochloric add, while 
eofigiilRted atbamen is not cbaiigetl. Coagulated albumen 
In urine is rediasolved by the nddition of a little potash, 
which has no efieet ujion an opacity i>rodaecd by the 
phosphates. 

Another test is the addition to tbe fiutpected solution vf 
a etroiiij: mineral acid ; when, if albiiuien be present, coagn- 
lation will take place. There i& only one source of eiTor in 
the application of thia test to the urine. If the urates !« 
present in very hirgu quantity, we iniiy have a deposit of 
atnorphoHS urates, giving an opacity something lite tlmt pro- 
duced by coagulated albumen. This error may he avoided 
by addint,^ mi excess of nitric ncid, which will clear np the 
mistnro if the deposit be due to the ]tresence of nratca, but 
has no effect upon albumen. In sudi a nase, also, no totbidity 
is produced by heat. "When the urates are depoeiteil, the 
turbidity makes its appearance more slowly thaa when albu- 
men is present. Various acid mixtures have been i>roposed 
as tests for albumen, but they seem to possess no advan- 
tages over nitric acid, which ia the one most generally em- 
ployed. 

The testa by heat and nitric acid are sufficient to detep- 
mhie the presence or al:«sfnce of aUuimen in any cleat 
tluid, if iipplied with the precaiitioiiB ab<»ve indicated. We 
may employ, howoTer, congulation by alcohol, or the albu 
miuimetcr of liccquerel ; but tlie tatter, like the saceharom- 
eter of Eiot and Soleilj is little used on account of the 



OEGAjnC PMKCtPLBS, 



d5 



eipecee of the instrument, and a certnin dexterity wliich is 
necessary for its exact application. 

Oi-Ujiit and Funct-ion (f AJ}inmen,-~Th<i ea-cnlkci albu- 
men ot' thu blood lias tte orifj^in iVoni a traneforniation of the 
products of digestion of the albuminoid cJcments of food. 
It ibrnis the great organic nutrient clement of the lilood. 
As we have ahiiady seen, it seems to he need in the forma- 
tion of the fibrin. In nutrition, it nniiergocB eatalytic 
trnnefurmatiiHis whifh re&iilt in tlio pct'tdiisi' organic prin- 
ciples of the various tiseues. In the circulnting blood there 
is a peculiftr condition of the albuminoid matters which is 
necessary to thtir mitritivc properties. Ecrnard has &hown' 
that the albumen of white of cg^ injected into the veins of 
an nnimal is incapable oi' aseimihition, and is theretVire re- 
jected by the kidneys, The fiamo result follows llie in- 
jection uf fresli Bcnmii, even from an animal of the same 
Hpeciee; but the blood itself can be injected without the 
appearance of albumen in the urine. 

In the passage of the hlnoc! through the liver, it hag 
been fonnrl that a small qnnntity of the so-cflHed altnrnen 
disappears; hut wc have not been able to follow it& traua- 
formittions. With the exception of the minute quantity 
which is discharged in the milk during lactation, albumen 
is never discharged from the body In health. Attcr being 
appropriated by the tiKsuee Jii the process of nutrition, it 
undergoL's changes in the wc-arsng^ out of the system, whi>uh. 
convert it Into excremeutitious matter. 



Alhiminose. 

This principle is intermediate between the organic nitro- 
genized elements of food and the so-calk-d albumen of the 
blood. It IB found in the blood in very email quantity after 

' Bmlsjkd, Z«fr)ii« tur fa Fropriitin PAi/tiiiloffiqntt rl Irt AUiraiionM PittJu>- 
Icgitput dr* lAtptidtx dt POrgoTiiinir, rarisi, 1SJS9, loine i,, p, 4fl7 



S6 



DfTBODDiTnON. 



digeatitm, almost iinmciiiiitely imdergi'img transfurnifltion 
iuto pI.'LBiiune nud acnue. It h nlso cuntained in tlic stomflch 
and smflll inteatiuea during digestion. It U uatttralljc fluid, 
like albiimeu and fibrin. 

In its behavior to reageiit-9, albumino&e presents certain 
diffarenees from albomen. It is congnlated by alcohol and 
nmuj metitlllc salts, but is not toiigulable by beat, and ouly 
imperfectly by nitric acid. It is coagulated by a small quan- 
tity of acetic acid, but the cooguluiu is dissolved in an excess 
of this agent, tlie lattur peculiarity distiHguit^liing it from 
caBcine, which \a coagulated by acetic acid in any quantity. 
Miallie states that albumintjse is more eudosniotic, or pasaes 
through niemhrance with much greater facility than albumen, 
which be says is absolutely Don-eudosraotic. Thia property 
favors Its introduction into the blood- 

Albiimliiose has its origin from the organic nitrogcnlzed 
elements of i'ood, which are nut uoly liquefied by the diges^- 
tive fluids, but undergo a catalytic transformation into this 
snbstance. By virtue of its eudosmotie properties, it pnssfiB 
into the blood-vessels, and is there convcrtetl into albumca. 
Mialhej who flitit described this BuhetancG under the nainu 
of atbiiminoBe, has shown that, injected into the veins of an 
animal, it becomes assimilated, and does not pass away in 
the uriije.' 

Caeeine. 

Thia organic principle is peculiar to the milk, and thexe- 
fore exiels in the body only during lactation. Like fibrin 
and albumen, it is naturally fluid, 

Cuseine may be easily extracted by the following process^ 
■wliich is recommended by Itobin and Verdeil.' "We add 
to the milk a few droi>8 of acetic acid, which precipitated the 
caseine aceoriipanied by the fats. The eoaguluni eeparaterl 



' UiALiu, C/ii'nif Apfiiquk d la J'tiyriofogif, Ttiia, 16CS, p. ISS. 
* Of. iil., tome HI, p. 3*1. 



OBOASTC PRISCIPLEB. Bi 

)m the liquid, tlien ivasbed, i& redissolrefl in a solution of 
carbonate of soda; this solution separates fioui tbe iUt wliich 
floats on the top, and can be completely removed at the end 
of twelve hours of repose. The Jii^uid thua freed frum fat is 
acidified by a few drops of liydrocbloric acid, and the caseino 
H precipitated perfectly pure." Obtained by this process, it 
is perfectly white, and insolulde in water, r-esenibling pot 
cheese. 

Casetne has certain marked properties hj which it is dig- 
tinguiebed from fllbnmen. It is not coogiilable by heat; 
is coa^ulahle bj the feebto vegetable, as well as the mineral 
fieide, and by rennet. This latter enbstance \& obtained from 
the fourth stomach, or aboiiiasus, of euctiug ruminating ani- 
mals, and ia the milk almost reduced to caseine, and mixed 
\rith the gastric fliiida. It i^ salted and dried, and in this con^ 
dition used in making cbeeae. Added to the milk in the pro- 
portion of titteento twenty griuna to a quart, it prodncea com- 
plete eoagnUtion, Aoeordirijr to Kobiii andVerdeil, caserne 
u precipitated by tlie metallic saJte, witb wluch it forme com- 
binations not to be distiiignisLed from like combination& of 
albumea.' It is a curiouft fact that caseino is siimetimea 
coag:u]ated almost instantly during thunder-storms. TliiB 
phenomenon we cannot ftilly explain; but the immediate 
cause of the coagulation sa the transformation of some of the 
sugar of milk into lactic acid. Oaseine retains its fluidity 
in tl)e milk by union with the carbonate of soda ; and when 
coagulated spontaneously, it may be restored to its liquid 
condition by the addition of tliis ealt, which does not render 
the fluid alkaline, but seeraa to enter into combination with 
the organic substance. 

Caseine baa its origin in the albumen of the blood, by n 
eatal;ytic; process i^'hlch takes place in the maniraary glands. 
In its liquid condition it constituted the important organic 
elemoDt of the milk. It is taken into the stomach of the 



' Im, aU 



88 



IKTKOnCCTIOK. 



iftfaut, coQTerteJ intu albiirainose, wliicli it resembles Tery 
closely, and nUorbutl by the bluoc], where it la converted into 
libriu auJ albumen, ami eontribates to the nutritioit of the 
Byatem^ At this period it cundtitatea almost tbe only nitru- 
getiizcJ element ol' I'uod. It is the only prosiiuato principle 
of tliia cEusa, with the escuption of a little umcosiue and the 
ctiloi'iag matter of the nrine and bile, which ia Jisc-harcjjed 
&QU1 tlie body in he&ltb. 

Panereadnfi. 

This 18 the oi^aniu principle peculiar to the pauereatic 
juice. Uernai'd was the first to describe its properties, both 
chemical and phyaiologieah' Before the appearance uf hia 
admirable monogragli on the pancreas it was confounded with 
albumen; but we sIuiU see that it posseaaes properties by 
which it may be distinguislied aa readily as caseine. 

Pancruatine exists in the pancreatic juice in large quan- 
tity. It i& naturally fluid, but very viscid. It i^ coagulated 
Ly heat, the titrong acide, and alcohol, but is unaifected by 
the fueble vegetable aciOe. It is distingoiislied from idbumeo 
by tiio faet that it is completely coagulated by an excess of 
snlpliate ot" magnesia. Its distinctive physiological ehai*acter 
ia ltd puwerl'ul digestive action upon certain eleiueiita of food, 
and its projicrty of forming an instautaneoua, complete, and 
very tine emuUion with liquid fats. 

Pttucreatine has its origin from the albumen of the blood 
by a catalytic cliange which takes place in the pancreiis. It 
gives to the pancreatic Juice ita digebtive properties. 

Fepain is the organic principle of the gastric juice. It 
ia hardly to be distinguished from albumeti, except by its phys- 
iological action in digoetion. The principle wliich has been 
extracted by varioua processes from the mucona membrano 

' Derjard, Slhnoire mr le Pancreat, Paria,]8fi8, 



en 



of tie stomacli, particulnrly iitlvr cronimeQcinp putrefaction, 
cannot be regarded as pure pejisin. It is uiKkmhtedly neces- 
sary to the digestive netiou of tlie gastnt juic^e, whiflj loses 
its phvsiologit-'al properties when this Bubatance Iiaa been 
coagnlated hy beat and separated by tihration. Its properties 
will be more fully considered under the head of digestion. 

Tliis is tbo organic principle of the general aeeretton of 
mucous membranes, presenting, liowevcr, some ditiercneeB 
in diflerent situations. In its general properties it closely 
resembles albumen ; indeed, what ia generally taken ns tho 
type of pnre albmaen, the ■n-hlte of egg, eUould strictly be 
called mncosjne, as it is the secretion of the mucoue niom- 
brane of tbe Fallopian tnbys, ftnd nlninst identical with Bonie 
specimens of pure mucne, bucIi as the eecretion at thu neck 
of the uteniB during gcstiition. It is imperfectlj coagulated 
by heat, but is thrown down by strong acids and the metal- 
lic salts. It is formed from the blood by tbe mucous folli- 
cles ; and, as a sniall quantity is discharged from tbe body, 
forms one exception to the genci-al hiw that orgn.nic nitro- 
genized priaciplee are never discharged from the body in 
liealth. 

Semimlid or Solid Prinoi^A. 

Most of tbe liquid elements which we have jnst considered 
liiive been found to be connected, directly or JuJirei^tly, ^Pitli 
the uutritiotL of tbe body, Tboiie which we now have to 
consider are all directly formed from the orgamt! principles 
of tho Idood, and constitute the organic jiortion of tlie econ- 
oiny. Here i* found to be the final de&tination of libriii and al- 
bumen, in nutrition ; for the organiu principlcB constitute the 
vital elements of aU the tiesiies, and are nouritthed exclusively 
by tlic^e elements of the blood. Wg include here the blood- 
corpu&clos which must be regarded as organized bodi^ 
ncarished like any of the tissues. The following are the prin- 



90 rsTRouL'cnoN. 

dplea in this group wbichare well established, aud naveucen 
filudied to a greater or lees estent : 

CryetaUinej 
J/uscJilijiej 
Osteins, 

Keraline. 

Globnline. — Tliia is a semisolid organic principle, con- 
stituting the greater portion of the blood-corpuacles. It is 
soluble in water, from wlilch it is coagulated by a teuipera- 
turo a littJe below tbe builing point. Excepting tbut when 
mixed with water it requires a much higher temperaturo 
for it^ congulatioD^ it baa nearly the same prope'rties aa 
ajbutuen. 

Like the rest of these priiidples, it exists in a state of 
intimate molecular uiuon with inorganic elements; but, 
eseeptionally in this case, is united with a small quantity of 
fat. In this condition it goee to Ibrm the organized structure 
of the blood-corpuscleB. 

Cryaitiffine.~-'T\m l^ a eemiBolid organic principle, 
pGf.uliir to the ciystalliiie lens. It prcficnia most of the 
characters of globitline, but h congulated at a little lower 
temperature, though higher than le, recjuired to coajrulata 
albainen, 

Mitsculin£.~—T]iii eemifiolid orgattic principle is peculiar 
to the uuucular tiesuD. It is im mediately dissolved at tho 
ordinary temperatiu-e by a uiistnreof ten parts of water with 
one of liydrocliloric acid. It may be precipitated troui this 
BoUitiou by neutralizing the acid, and tho |irecipitate is re- 
djasolved by an alkali. It ie always united with a consider 




OBOAKTC PBINdPLES. 01 

able quanHtj of inorganic sfllts, in wliieli tlie ptospliates 
pj-eJominate. 

MuscuUne, m eombication with inoirgattlc substancea, 
goes to (urm the muscles; but m addition, is mterestiug a.& 
beiug by far the most important and abundant nitro^enizud 
elenjeiit of food. It is the great Bonrce of tho fibrin and 
albumen of the blood of miui and of the carnivorous animaU. 

Osiaine. — Tliia organic principle, natnrallj solid, is pecu- 
Har to the bonei. If the enrtby matter of bono be dissolved 
out witb dilute lij-drocliloric add, the residue is nearly puro 
osteiue. By boiling with, water it is tnuisfurmeJ intoffelafine, 
a soluble substance differing in many rcspocta from osteine. 
According to the cxperinientB of Ma^endie^ fresh bones 
poe«e86 considerable nutritive jjower, which ia entirely de- 
stnrj'ed lij prolonged boihng. It enters into combination 
with large quantities of earthy salts, to form the bonee. 

CartUitgine. — This principle holds the same relation to 
cartilage as ost^ine docs to bone. By prolonged boiling it 
is tr&usformed into a substance reseiiibting gelatine, called 
by Miiller chondriue. This presents many points of diflerence 
troni gelatine, whidi renders it probable that the transfor- 
mation of cartilage into bone, does not merely consist in the 
depuf^ition of nalcareous matter, but ako tho gnhstitution of a 
nevr organic principle, 

J^iaatLcln^, — ThtB is the organic principle of the yellow 
elastic tisane and the investing membrane of the mugcular 

fibres. According; to Rohin and Verdcil it is slowly dissolved 
by suli^horic, iiilrie, and hydrocEiIoric acids, and these solu- 
tions, diluted with water, are not precipitated by alkalis, It 
i» possessed of great etreiigth and elasticity. 

Kerailne. — This is an organic principle, found in the nails 
and hair, about wbich we know very little. It differs from 



92 ixTRODccnos. 

tbe other principles in the fact that it ie not diseolved, but 
decomposed hy potash, giving oA'aminoniaeal vapor. 

These substnnces have been classed with the organic ni- 
trogenizcd priuciiples^ from tlie fact that tliey cuntain nitro- 
gen ; but they do not eecm to be endowod with the pefnlkr 
properties which, characterize this class, with the exception 
perhaps of hfPmaglobine and inflaniTic. Ae a peculiarity of 
chctiiienl ennetitntion, they all contain iron, which is niolee- 
\ilaHy united with their other elements. The following are 
the principles of this gfonp : 

Hiliverdintf 

Urmmcifie, 

TFa:infigld>>ne. — This is the red coloring matter of the 
blood, and exists, intiiimtcly united with globuline, in the 
blood -coi-puacks. The iron which it contains can be rwiLlily 
demo net rated, even in a fiiiigle droj* of blood, by tlic ftdlow- 
ing process; To a email quantity of bluod in a walcb-glaas 
wo add a drop of nitric acid, then evaporate slowly over a 
lamp, when finncs of nitrous acid are driven ofi", the iron 
takes oxygon and is converted into a peroxide. If wc then 
add a drr»p of tlic enlphocyani<le of pchtassium, we produce 
the charncteristie red color of the Eiilphocyanide of iron. 
Separated from the hlnod, hfl?niaglobine is soluble in ether 
and hylling alcoliol, but insoluble in water and in acid*. 

"VVe Jo not exactly imderstand the mode of formation of 
lisemaglobine, but pathology teaches ns that it is au essential 
principle of the bhfod. In certitin cat^es ol' ana^uia, when 
there is extreme pallor andconsetincully deficiency of Inrma- 
tine, the adniinistmtlon of iron in any form induces tbe for- 
mation of this substance, restores the normal constitution of 



COt^RIXG MATTERS. 



93 



tnecircimting' fluid, ami relieves tJie ^c-iienil effects of" the 
deliL'ioiiey of culuriiig mntter ; au cffet-t which t^annot be pro- 
duced by the most nutritions articles of food. Ila'ina^lobine 
is pro1i:i!ily destroved in tlie organisnij and ftiniisLea mftte- 
rifll f<^r thi; Ibnimiion of the other coloiiug mattc-i^, 

Jfc/nnitw. — This substance resemlik-a hienrnglobine. con- 
taining, however, a smnller |iro]ifirtion of iron. It is of a 
brownish color, and is fonnd in all parts of the body where 
pigment exists ; such as the choroid, iria, hair, or epidermis. 
It exists in the fomi of graimlationB, either free or enclt^eed 
in epithelifl! cells. In a]l probability It is formed l>y ft trans- 
fomiAtion of hssm-tglobine. 

Jiilit'erdlnfi. — This is a grcenisli-yeflow coloring matter 
peculiar to the bile. Extracted I'ruin the bile, it is insoluble 
in water, but soluble in alcohol or ethor. It contains iron in 
nefti'ly the same proportion as hiemagh-'biiie. 

Biliverdino is formed from ha?mnglobine, entcre into the 
constitution of the bile, ia dtschHrgtid into the small intes- 
tine, and, after undergoing certain modifications, ia dii- 
charged from the body in the fteeee^ 

Urrosacine. — This is the principle which gives the amber 
ColoF to the uriiie, Ai'ter extraction, it is insoluble in wnter, 
but eolnble in alcohol or ether. It exists iji the uriuc in very 
email quantity, and is formed in the kidney, in at! probability 
at the expense of the hsemaglobine. Urrosaeine and biliver- 
dinu are the two coloring matters disehargcd from the body. 

Shimmanj. — A review of the individual properties of the 
organic nitrogenizid principles shows grent differences in 
tbeir physiological, and very slight dltfbroucos in their purely 
cbeinicMl eharactorrf. It i& h fwct too apparent to retinire 
argument, that their chemical history is of little importanco 
compared to a study of their vital properties. In fact, ro- 

searehea into their ultimate composition^ with the eicep- 

7 



u 



DtniODtlCTION, 



tion that they Lave eliowii tliem all to contain nitrogim, ai*e 
nlniost witliiTUt value. Without exfeption they are al! in a 
ttate of tntlmate molecular union wltU inoi^anic matter, and 
in tliis union iiioi-ganit! eorapouinia become endowerl with 
life ; tliat is, the inorganic parts of the body, aa the catoareona 
elementa of bone, taken up by the blood ■with the worn-out 
OTganic print'iples nnd undei^joinj^j constant waste, are eapa>- 
bio of eelf-regene ration. 

TAf vitality thig {mjiart^l to inorganic matter^^ and tAe 
fuel tlifxi n^Wi^f the oyganlc n&r hwrganle elements are alone 
capalle of eagd^ging in t/ie j)haio7tifr<ri of life, cannot he too 
fully ijisisledttipon. Both are taken into the body &$ food, 
are digested, agaimilatcil, and finally discharged, always in 
coiiibinHtiou; the organic principle* changed, and conrGrt.e(l 
into cxcrenientitionB BubstanceSj and the inorganic princtples 
unchanged. 

The readiness with which the organic principles are cou- 
vertcd one into the other by eatnlysia must also be appre- 
ciated, as well aa the ctinstttnt operation of this process in 
all the phenomena of life. Even albumen, taken in a& foo<% 
must be Converted into albnminose, and agaiti into albumen, 
before it is capaHo of buildiug up the tissu^j and all the 
nitrogenized ai'ticles of food are converted into tlie &anie eub- 
fltance, regeneraling the blood, and through it the body. 

In the economy we find two great divisions of organic 
elements: one, which is nutritivCj and tlio other, which, 
forma the great part of the tiagu^. By simple contact, the 
plastic, or nutritive, principles are mysteriously converted 
into the varied elements of tlie tirganisni, and take with them 
the inorganic elements necessarj" to tlio proper coniititDtion 
of the parts, 

It IB only with a just appreciation of these general princi- 
ples that we urc able to study intelligently the special funetioiu 
of i-espirntion, circulation, digestion, absoi-ption, eecretion and 
excretion, which are ail tributary to the complicated function 
of nutrition. 



i 



CHAPTER I. 

THE BLOOD. 

Geneni] coiuideraUons — TransfuBion — Qoantity — General characters — Opacity 
— Temperature — Specific gravity — Color — Blood - corpuscles — Development 
of the hlood-corpuBcles — Leucocytes, or white corpuscles — Development of 
leucocytea — Composition of the red corpuaclea — Globulino — EeGmaglobine. 

In all ages, even before pliyeiology became known as a 
diBtinct science, tlie importance of the blood in the animal 
economy has been recognized ; and with the progress of 
knowledge this great nutritive fluid has been shown to be 
more and more intimately connected with the phenomena 
of life. It is now known to be the most abundant and highly 
organized of the animal fluids ; providing materials for the 
regeneration of all parts, without e.xccption, receiving the 
products of their waste and conveying them to proper organs, 
by which they are removed from the system. These pro- 
cesses, on the one hand, require constant regeneration of its 
constituents, and on the other, constant purification by the 
removal of effete matters. As it has been found desirable to 
preface our study of physiology with a history of proximate 
principles, showing the chemical and physiological properties 
of what may be considered as the permanent constituents of 
the body, so, before considering individual functions, all of 
which bear finally on the great process of nutrition, we should 
have an accnrate knowledge of the anatomy and chemistry 



06 



THE DLOOD. 



of -what 18 m&st njiproprifltoly failed tlie great nutritive fluid. 
It has been gatd tlat al! parts are depemlent tm (lie blood for 
nottri&hmeTit. Those tisauee in which the processes of nutri- 
tion are active arc supplicti witli blood by veescls; but goin^ 
lees hif^bly organized, like the epidcrmie, Imir, cartilage, etc., 
which are sometimee called extra-vaflciilar hecjiuse they are 
not penetrated by blood-vessels, are none the le^ dcfjendent 
upon tlie fluid Holder consideration; imbibing, aa they do, 
nourishment from the blood nf adjacent parts. 

It must be remerahered that in nutrition the tissues 
are active, selecting, appropriating, and modifying mnterial 
which is eiaiply fuj-idshcd by the blood ; and as the real vital 
force which governs tliese processes resides in the tifiSucs, ten- 
dencies of the Byetem, snch as the tuherenlar, scrofuhms, or 
eaneerouH diiitheeea, wliidi lead to discirdercd nntritioo, muBt 
have tlieir seat iu the solids, and not in the circulating fluid. 
The first cause of theac conditions may lie iu a disordered 
Btnte of the blood, from bad nourishment, from tbe introdnc- 
tion of poisons, such as malaria, or the emanationa from [ler- 
Bons afleeted with contagious diseases, and under some cir- 
cumstances tlie elimination of these poiaona may he effected 
through the blood ; but when they exist in the blood, they 
either become Sxcd in the sygtem, or are thrown ofl". "We 
must regard most of the morbid actionfi which are dependent 
on diathesiBj as the result of a vice in the tiseuo itself, not the 
blood with which it is supplied- It is none the Iras essential 
to hoftltli, however, that tbe blood should have ita proper 
constitution. 

The final importance of the blood in the processes of 
nutritiou is evident; and in animals in which nutrition is 
active, death is the immediate result of its abstraction in large 
quantity. Its immediate importance to life can be heanti- 
fully demonstrated by eipenments upon inferior animals. 
If we take a email dog, introduce a cauula tlirougli the right 
jugular veia iijto the right side of the heart, adapt to it a 
Byringe^ and suddenly withdraw a great part of the blood 



TEAsayraios. 



87 



from the circulation, immediate euspension of all tLe vital 
processes i& the lesull:. If we tlien retura tLe blood to tbo 
Bj-steni, tbe animal is ae auddtaoly revived.' To perforin this 
experiment satis fnutorilj^ ■we must accurately adjust the ca- 
pacity of the Bjriiige to the size of the animal. Carefully 
performed, it h very striking, 

Tj-ansfusiori. — Certain caua(», oneof irhich is diiniautioa 
ill the force of the heart after copious hfemorrhage, prevent the 
e&trape of all the blood from the body, even at^er division of 
the largest aiieries; but after the arrest of the vital funetioufl 
which follows copious diticliargea of thin fluid, lil'e may be re- 
stored by the injection into the ^'easels of the same blood, or 
the fresli blood of another animal of the same spec-jes. Thia 
observatioa, which was first made on the inferit>r animata, 
baa l>eea ajjplied to the Liimau subject; and it haa been as- 
certaiaed tJiat in patieatg ginking under hiemorrha^re, the iu- 
troduclion of even a few ouaecs of fi-esh bloi^J Mill restore 
the vital forces for a time, iuid Bumetimea pertnanently, Tho 
ojjeration of transfusion^ which consists in the introduction 
of the blood of one individual into the vessels of another, 
waa performed upon auiinak in the middle of the seven- 
teenth century, and was soon after attempted in the hiuaaii 
subject. So great wiw the eutliusiasm with which &oine re- 
ganlod these experiments, that it was even thought posaible 
to effect a renewal of youth by the introduction of young 
blood into ilie veins of old persons ; and it was also pro])i]8od 
to cure certain diseases, such aa insanity, by an actual renewal 
of the circulating fluid. Tlieae ideas were not withrmt ap- 
parent foundation. It was stated in 1GC7, that a dor;, old aud 
deaf, had hitj hearhig improved and was apparently I'ejuve* 
nated by transfusion uf bWd from a young animal. A year 
later Deuya and Euimereta published tfie jase of a maniac 
who was restored to health by the transfusion of eight ouncea 



• DnuxBs^ I^fona mr Itt Liquida de I'OrganunK, tome 3., p. i\. 



»u 



THE BLOOD. 



of Uood from a calf; and aiiotlier case was rcpori^d of a man 
whij iTfls ctired of leprosv by tlie same nieana. But a reac- 
tion fullowed. The case of insanitj, wliicli was apparently 
eureil, tuffored a relapse, and the patient died during a 
tliL-rl attempt at transfusioti.' It ifl almost Tirmecessarj' to 
fitly that thcBO extnivagant expectations were not realized. 
In fact aume operations were foUowed by audi diaastrons coti- 
Bequenees, that the pmctice waa forbidden by law in Paris m 
16GS, and sooti fell into difiusB, 

TrausfusioQ, -with more reasonable applications, was re- 
Tived ia the early part of thift century (181S) by Blundell, 
"who, with (jthei-s, demonstrated its oeuasiuual efficacy in dee- 
peratchffimoiTliage, and in the laat etagea of some diseases, 
eapet^lally cholera. There are now quite a number of eases on 
record wliere life has been saved by thifl means; and often- 
timea, when the result has not been go happy, the fatal event 
has been cotieidecably delayed. In a case wbich occurred at 
New Orleans, when the system was prostrated by au obscure 
ftflection and life became nearly ejttinct, about seven onneea 
of blood in all were transfused in three operations, within two 
hours, with the pal|jali]e eifeet of prolonging life for from 
twuWe to sixtran houre.' B6rard had collected from various 
Bources thirteen observations of hemoiThagc, which would have 
been fatal, in which life was pennancntly restored by lh« 
injection of a few ounces of healtliy human blood. In all 
but two of the&e cases the hemorrhage waa uterine.* 



I PhiliHophirai Trau*ai^lii>t\*, IrOndon, 1868, p. 710, rt rrq. 

* In llua ciriu tbu putient tufl'ered extiriae proBtration aflei Hie ^«liT«ry ofa 
BcTtn DcI a half muullis' dill'l. Tfals coQtinutd for n few dtip, tni at ilie tiiu? 
of irawtAuion, tlii' pulvii wua 140 nad tvt.v fvcUe; n-^piriidun^ tis. to eJghl per 
inlnuti^l noi^triU cotnpTt'T^ed ut eAvb iuppii'atinn; surfnuc cool ; counU'Duni-i' Hip- 
]Kii;rAtii?, and Uio cdiua m profound that tlic patkiil could out be an>ut>t(I. Mut 
each t»ati4fypit)ii Hid lijia becnme more fiorid, th.c noElrila dilated in inftpiration, 
■nd ibc BurliLue becjinii? num^or. The i-ntitut Ijvci! Iwnaly-fonr boiirs fiDcr th« 
Ant operation. TliG blood vtt. leiva IWidi Ibe arm of a licalcLjf male and umit6- 
fkiacd imWiwJ'iali-'l)' into l\iv nii-<.Iia.n ceplinllc vein, 

* B£R&Ri>, Conn dt T%j/mo!off)f, Pari*, 18H1, Home iil, p. 219, tt wj. 



TBANSFCSIOK, 



09 



Since this tinm a. great many experiments on trail sfiision 
in animal:* Iiave been performed, with rerj interesting ri?siilts. 
Pr(-voat and Dvimas' liavc &lii.i\vn, tlifit wliile an flntmal may 
be restored after bemoniinge bv tlie t-ranfiiTision ot delibripated 
blooJ, no sucli efl'ect follows the intrtxJuction of the bcrurai ; 
allowing tLat tlie Tiriljiiig iuflueiico in all probability resides 
in tlie eorj'iibeles. Yarimis obeervere have also abown, lilint, 
thonf;h iin nniTiiiil iiioy bi' teniporRrily revived by tlie injection 
of ^lelibriijjitcil bloud from an animal of a different epeeieSj 
dcatli follows tlie operation in a few days.' Browti-Sequai'd 
haftslnjwn that in purts detaclted from tbe body, after nervous 
and muscuLfLr irritaliility have disappeared, tlic&c prciperties 
may be restored for a time by the injection of iresh blood.' 
He alsu fepyrts. a curious experiment in wLIl-Ii blood waa 
pa^scl from a living dog: into the carotid of a dog jitet dead 
from perituiiitia. The animal was so far revived as to EutEain 
himself on hh feet, wag his tail, eU:., and died a second tj'me, 
twelve andabalfLrmrsafter. In thiacxpcrinieut inibufllatjuu 
was cmphjyed in addition to the transfusion.' 

It may then be considered estahliahed, that in nnimalti, 
after ha-iriurrhage, life may be restoi-ed by injceting the blood, 
defihriuated or not, of an animal of ttte same Bpec^ies, pro- 
vided it be inlrcKhnied slowly, withont odnnxture n-ith air, 
and not in too great quantity. If, however., the blood of an 
animal of a, dift'erent species be used, life will be restored but 
for a short time. Death oecure after the transfu&ion of blood 
in this instiwice, only when tbe animal receiving it lb oxaan- 
gnsine, and the blood of an animal of a dificrent species is 
substituted. If the animal be not exsanguine, a little blood 
can be supuradded to the mass from an animal of diti'erent 
s^Mjeira withont this result, as is shown by the experiraenta 



• BibcjiitD, «/i. <i7., lotns lil., p. 210. 

• >Iu.KE-Ri>w«iii», LtfTHU rur In I'ltj/tnilogU fi VAnaUtmU ComjMxrh^ tanw i^ 
|V Hi H fe?. 

' Jovmal de la Pfti/n^Jo^, toDie :., p. lOfl. 

• Ibi.V p. 'ttflS. 



100 



THE Bt-OOD, 



ftlreadjT allurled to, of translusiou of the blood of a calf into 
tlic Tclua of a man. 

In tliQ hnmaii subject, especially ftfterLfflmorrljagef the 
vital powers are soinctinies restnryti by careful tninsfusion 
of human blood, with the nbove precautious; reuiembmng 
that a very email quantity, three or four ouuccb, will sonic- 
timea be sufficient. 



Quantity of Blood, — The determination of the euttro 

quantity of blood contained in the botly h a queetion of great 
interest, and haa long engaged tlie attention of phvEiologifits, 
without, however, absolutely definite results. Among those 
who have experimented on tliia point, may he uieotioned 
AlloQ-itouhuu, Herbst, Fried. Hoffmann, Tulentin, lilake, 
Lehmaun and Weber, and Vierordt.' The fact tlint the 
labors of these otnineut obserTers have been ao far unaucceaa- 
ful in determiuing definitely the entire cjuatitity of blood, 
shows the difficulties which are to be overcome before the 
question can be entirely settled. The chief difficulty lies iu 
tlie fact that all the Llood is not discharged from the body 
on division of the largest vesaek^ a» alter decajiitation ; and 
no perfectly accurate means Imve been devisetl for estimating 
the quantity wbieh must iJways remain in the veapcla. Tlie 
ostimiites of experimentera present the following wide difter- 
eneca. AJlen-Moulins, who was one of the tirat to study this 
question, estimates the quantity nf bh-nnl at one-tweutieth 
the weight of the entire body. The estimate of Herbst is a 
little higher, Hoffmann estimates the quantity at one-iiftL 
theweight of the body. These obsen-ers estimated the quan- 
tity remaining in the system after opening the vessels, by 
mero coujceture, Valentin was the first who attempted, to 
overcome this difficulty by exi>enment. For this pttrpoae 

'The rottd^r is rerL-rrL'tl to tlio wnrks of Lflnget {Ifiiitiuitiyif, PiriA, 18119, 
toms ii., p. iiO tt «y,) 0H'l Mltnp-Erlw.irila {Plitfrnulogit, Pftri.*, ISJ?, tome L, p. 
SOS *{ uq,), Tur s mtjre «'Klen<3<^ mxrount of tlie vnriuua cipci-iii><-nM whiL-h liarc 
tKvn mKly wilh ti vie« <(f duCurniilnlii!} tlie eiiUri.' ijuanliij of WooJ in die body. 



^PAJrmr of blood. 



10] 



be employed tlie fijllowing process. Hu tciok first a Binall 
quantity of Lilood trom an nnirnallnrpiiriingeaof coraparisou; 
then iujt«tc'd into tLevueeels b known quantity of a saline solu- 
tion, and taking another specimen of blood some time nf^er, 
he ascertained by cvaporatiou the proportion of water "whicli 
it contftined, uouipared with tho proportion in the first speci- 
men. He feaaoned that the excess of water in the second 
Bpecinjen over the first would give the proportion of the water 
introduced, to the whole mass of blood; and na tlio entire 
quantity of water introduced is known, the entire quantity 
of blood eonld be deduced thert'from. Suppose, for example, 
that the excess of water in the Befiond t'pecinien should be 
one part to teiJi of the blood, it would show that one jwrt of 
water had been mixed with ten of the blood ; and if we 
had injected in all five onncea of water, we would have the 
whole qnantity of blood ton timee that, or fif^j ounces. 

ThSe method is open to the objectiun tliat it Is impmssi- 
ble to take note of the processes of imbibition and exhalation 
whicli are conetantly in operation. Taking it for what it is 
worth, tho eBtiraateSj applied to the human eubject, give the 
weight of blood as -^ that of the body. 

Blake estimated the quantity of blood by an analogous 
process, injecting a knoWn quantity of enljihate of alumina 
into the vefl&els, estimating its proportion in a epef'imen of 
bl(jod, and from that deducinf^ the entire r[nantity. He gives 
the pioporfion of blood in dogg as from Diie-nlnth to one- 
thii-d the weight of the body. The objection we have men- 
tioned applies also to these experimenta. 

The following prw^ess, whit'h i?, perhajip, least open to 
Bonrees of error, was employed by Leliniann and Weber, and 
applied directly to the human subject, in the case of two 
decapitated crirainals. Tiieae observere c&tiiuated the blood 
remaining in the body al\er decapitation, by injecting the 
vessels with water until it enine through nearly colorless. 
It was carefully collected, evaporated to dryness, and the dry 
residue assumed to rejirewnt a certain quantity of blood ; the 



iu3 



THE BLOOD, 



proportion of dry reeidue to a definite quantity of blood 
having been previously ast^ertained. It' we eould lie certain 
tliat only tlie solid mattor of the blood was thus removed, the 
estimate would be tolerably acciimte^ As it is, we may con- 
sider it as approximating very nearly tu the trutli. We quote 
the following at'coiint of these obuervations; 

" My friend, Ed. Weber, deterraiTied, with my ooOpera- 
tion, the xv«^iglitg of two tritninals both before and after theiP 
decapitation. The quantity of blood which escaped from the 
body was determiued in the following manner: Water was 
injected into the vessels of the trunk and head, until the fluid 
escaping from the veins had only a pale i-ed or yellow color; 
the quantity of the blood remaining in the body was then" 
calculated, by instituting a comparison lietween the solid 
residue of this pale-red aqncona fluid, and that of the blood 
which tirat escaped. By way of illustration, I subjoin the 
results yielded by one of the exjierimeiits. The living l>ody 
of one of the criminals weif,^hed GOjI'iO grammes (132"7 
jjounds), «nd the same body after docapltntion 54,600 gram- 
mes; consequently 5,540 graniTnea of blood had eacaped. 
2S*5iJ0 graimnes of this blood yielded u'SU grammes of solid 
reeidue; 60"5 grammes of Eangiiineous water coUet^ted after 
tlie iujectioii, contnineil S"T24 gralnmes of solid tubBrant'eH; 
6,050 grammes of the eanguineous water thiit returned from 
the veins were collected, and these contained 37"24 grammes 
of solid residue, wliieh corresponds to 1,98'0 grammes of 
blood ; consequently, the body contained 7,520 grammea 
C16'59 pounds), 5,540 escaping in the HCtof decaiutatioo.and 
1,980 remaining in the liody ; hence, itie weight of the wholo 
blood was to tliat of the body nearly in the ratio of 1;8. 
The other experiment yielded a precisely eimilar result, 

" It cannot be assuuied that such ex]ierimcnts ae these 
poBfeess extreme accuraeyjbut they ap]jear to have the ailvau- 
tage of giving in thifl manner the minimnm of the blood eou- 
tained in the body of aji adult man ; for although some solid 
snbatflnoes, not belonging to the bloodj may be taken np by 



QDASnTT OP BLOOD. 



103 



tlie TTAter from tlie paretich^-nia of the organs peroieated witli 
capillarj vessele, the excess tim^ obtained is B(J corupletelj 
counteracted by the duficieufy tause'l bj tlie reteulion of 
Bome blood in the capilhu'ios, and in part by transudation, 
tlint inir cstiinatti of the quantity of Llood contained iu the 
hoinnn body may ba considered as sJightly below tlie uctnal 
quantity."' 

In extreme ohetsity, the wt-igbl of the blood would not 
bear a natural ratio to that of tlie body ; but from the data 
-nrbich we have at onr coinniand, we inny etate the proportion 
iu a welJ-formtfl man to be about 1 to 8, ortliG wliole qmnntity 
of blood at froin 10 to 20 pounds avoirdupois. The quantity 
of blood undoubtedly varies in the same individual in differ- 
rait ccmditinns of the system ; and tliese variations are ftilly 
as important, in a physiological point of view, as the entire 
(quantity. 

Prolonged abstinence has a notablo effect in dimiuisbiug 
the tDii^s of blood, as indicated by the small quantity wLidi 
can be removed from the body, undei' these circum&tances, 
svttli impunity. It bos been, esperimt-n tally demonstrated* 
that the entire quantity of blnod is considerably iucreased 
dnringdigestion. Bernard drew from a rabbit wciy;hing about 
2^ n»s., during digestion, over lOJ ounces of blood without 
producing death; while he found that the removal of half 
that quantity from an animal of the tame eize, Casting, wna 
followed by death. In Burdachj' we find a case reported by 
"Wrisberg, of a female criminal, very plethoric, from whom 
21 lbs. T} ounces of bbhod flowed after decapitation. As the 
relations of tbe quantity of blood to the digestive fiinetion 
are so important, it ia unfortunate that in the obaervationa 
of Lclmiann and Weber, the cuuditiona of tbe eystem in thia 



' liDrcura, Ph^ri'iU^ieal Cfieaiigtri/, Pliilmlelpliti, 186i, vol, i., p. 638. The 
weights of tbe hni'y acd Ihi" I'lmire ijiiniitilT uf bluod have heva rcductfl rroin 
prsiiiii))<^ III jKiunde UTnmlM|iotA, 

' HusiiiD, Lirpiiiiei tie Wrgnniime, tome i., p. 419. 

' OjK dl^ lome vi., j>, lltt, 



10* 



i"espc(?t were not noted ; n cireumqiance wliicli would liavo 
added nuLterially to their value. 

It 13 tljua evident that tlie quantity of blood iu the body 
is considerably increaBeJ during digestion ; but as to the 
extent of this increase, tc eaiinot yet form any definite idea. 
It is only shown that there is a very iiiarkeJ diflereuco in 
the effects or hiemorrhage in aniiualB, during digestion and 
fasting. 

The reaction of the blood, which has been determiued 
after the globules have separated so as to allow the applica- 
tion of torit pajicr to the dear plasma, has been found tu l»e 
nniformly tiLfcaliae. 



Phi/fiml Characiers of the Blood. 

Opacity. — One of the firet physical characters of the hlood 
which attract our attention is its opacity. This dej)end8 
upon the fact that it is not a homogeneouB fluid, hut com- 
posed of two dielintt elements ; a clear ptnsma, and coi^pns- 
cles, whitrh are nearly as transparent, but which hare a di!- 
ferent refractive power. If both of these elements had the 
eatne i-efrtLt-tive power, tlie inixtnre would present no obstacle 
to the passage of light; but as It is, the rays, which are bent 
or refracted in passing Iroui the air through the plasma, are 
again refracted when they enter the corpuscles, and again 
wlien tliey pass from the corpuscles to the plasma, so that 
thev are lost, even in a thin layer of tlie fluid, Tliia loss of 
light in a mechanical mixture of two transparent Utjuida of 
unequal refractive ]K:>wer can be demonstTHtod by the tbl- 
lowiiig simple experiment. If to a little chloroform, col- 
ored red, clear water be added iu a test-tuhe, these liquids 
remain distinct from each other, and are both transparent; 
but if wo agitate them violently, the chloroform ie tempo- 
rarily subdivided into globules and luJxed with the water ; 
and as tiicy refract light differently, the mixture u opaque. 

Odor. — The blood has a faint but cliaracteristic odor. Thia 



PUTSICAL CEAKACTEES. 



105 



Mfty be ctevolopeO niore gtrongI_)" by the addition of a few' 
dfnpS of sulphuric nuid, wlieu aii udor, peculiar t-u the iiuimal 
wliose blood ire are exumiuing, becooies very di&tinct, 

Temperature. — The temperature of the blood is generally 
given as 98* to 100" Fabr., but recent esperimenta have 
shown that it varies considerably in ditFerent parts of the 
circnlatory syst-em, indepeTidently of ex|>oaure to the refrig- 
etating^ InfluenfO of the atinospUere, By the use of very 
delit-'ate registering thermometei"8, Bernard line succeeded in 
eatabliihing the fallowing facta with regard to the teinpeniture 
iu viiriuiis ]iarts of the circulatory system in dogs and eheep : 

1. The blood is warmer in the right than in the letl cav- 
of the be nut. 

2. Il is warmer in the arteri^ than in the veins, with a 
few esceptions, 

3. It ie generally wflmieF ifl the portal vein than in the 
abdominal aorta, imJepeudently of the UJge&tive act. 

4. It ia constantly wunuer in the hepatic than in the 
portal veins. 

lie found the highest teinperature in the blood of the 
bepaiic vein, where it ranged from 101° to 107°. In tlic 
aorta it ranged from 09° to 105*. 

"We may aasuine, then^ in general terms, that the tem- 
perature of the blood in the deeper vessels m from 100* to 
lOr Falirenheit." 

Bpec{fc Gravlfij ofihs Blood. — According to Kobiu, the 
specific gravity of dctihrinfited blood u from lOo'i to li"i57, 
Wing somewhat less in the femftle than in the mfde.' Its 
density vflries very considerably under difierent conditions 
of digestion. 

' TbMe tKls were taken Trom lli« lectures of Bernard, " Sir In Lu[uidf» do 
f Or^aaiimc," Psriit, 1850, 111 twci Toliimes. The lirgt volume is dtvuted ly tUo 
lilwfl. "nil tbt subject of ttmpitTaliire is vtrj tlioroughly inieBtlgilcd 

" JtoBis, Lt^is ntr ItM Humeun, Paris, 1874, p. 48. 



iOfl 



THE BLOOD. 



Cbl^r of the Bhfod.— The color of tlie hW»\ U doe to tlie 
Corpuscles. In the arterial system, it is unttormly ted. In 
the veins it ia dark blue and sojnetiinea almost blat^k. This 
difforenee in color between the blood in tlie arteriaJ aud iu 
the venous ejetem was a matter of controversy at the time 
of Harvey. By the discovoi'er of tlie oireulation, the differ- 
ence, which is now imiveraally known and admitted, as re- 
gards most of the veins, wna supposed to be merely accidental, 
and dependent on external causes. Fifty years later, Lower' 
flciiiouritratcd the change of color fn the blood as it passes 
tbryugh tbe lungs, and associated it with the trne cause; wV., 
the absorption of oxygen. The color in the veins, however, 
is not constant, JLuiy years ago, John Ilunter obsorved, in 
a case of syncope, that the blood drawn by venesection was 
bright red;' and more recently Bcniai"d has demonstrated 
that in some veins the blood is nearly, if not quite, as red aa 
in tho arterial eyetem. The color of tlio venous blood de- 
pends upon the condition of the organ or part from whieh it 
is retnraed. The red color was tirat noticed bj Bcniard in 
the renal veins, where it contrasts very strongly with the 
black blood in the vena cava, lie afterward observed that 
the redne&s only esisted during the functional activity of the 
kidneys ; and when, from any canso, the 5e<;retion of nrine 
vra& arrested, th^e blood became dark. He was led fi'om this 
observation to examine the venous blood from other glands; 
and directing his attention to those which he was able to 
examine duruag their functional activity, particulwrly the 
salivary glands, found the blood red in the veins during 
BWTction, bnt becoming dark as soon as secretion was arrested, 
The3.e observations- may be easily veritied by opening the 
abdomen of a living animal so as t» expose the emulgent 
veins, introducing a camila into the ureter so as to Ije able 
to note the flow or arrest of tho urine. As long m the nriae 

' LcwiH, Tractahu Je CanU iUat de .Volu it Oolore SaiiffitiiiU, AmflcEotlain^ 

lilrtft, p. 18' I. 

• The IVurk* of John Uajiwr, Fhikdfl|jliin. ISlft »ol. lii., p. 9$. 



PHTSTCAI. CILARACTEBS. 



107 



eontinucs to flow, tbe hhoA m tlscse vesscU wiU be bright 

red; Lut when secretion becomea arrested, (is it soon tloea 
after esposufe of Uie ofgftne, it presents no ditferenee from 
llie blood in tlie vona cava. In the siibraajtillarj glatid, by 
the galvauLzation of a certain nerve, wbieh he calls tbe motor 
nerve of the gland, Beriiai-d has been able to prodiic0 secre- 
tion, and by the galvanization of another nerve, to arrest it ; 
in this M'ay changing at will the color of tha blood in the 
vein. It has been found by tbe ^ame observer that dlviaion 
of the eynipatlietic in the netk, wblch dilates the ves&cla nitd 
incrciuies the supply (if blood to one side of the head, produtca 
a red colur of tbe blood in tbe jugular. He has also fonud 
that paralysis of a member by diviBion of the nerve has the 
Bamy eftVft on the blood returning by tbe veins. ' 

Tlie tixplanntiou of these facta h evideut wlien we reflect 
upon the reasons why the blood is red in the arteries and 
dark in the veine. Its color deijends upon the corpuBclea ; 
and sa tbe blood passes throngh the lungs it loses carbonio 
acid and gains oxygen, changing front black to red> In its 
passage tbroiigh the ciipiilaries of the eyeteni, in the ordinaiT 
proceeaes of nutrition, it loses oxygen and gains carbonic acid, 
changing from red to Hack. During the intervals of secre- 
tion, the glands have just enough blood ^ent to them for their 
nutrition, and the ordiniirj ioten-biiiige of gases takes jilace, 
vith the consequent change of color; but during their func- 
tional activity, the blood ia supplied in greatly increased 
qmiutityj in order to fumish tlie watery elements of the 
BocretionB. Under these circumstances it does not lose 
oxygen and gain carbonic add in any great quantity, as has 
liecn <k'uiousl rated by actual analysis/ and consequently 
€!xpcrienceft no change in color, When filaments of tbe syin- 
pRthetic are divided, the Ycpsela going to tbe part are dilateil, 
•nd the fiujiply of hlood is increased to sucdi an extent, that a 



* Bmsjinn, op. eti. 

* UninilitiBlint Icrturtrs dfelilTc^feil bj Berjutd fcn Lb* College of France iltirinj 
tbe mmiilier uf ISAl. 



lOS 



TUE BI.OOD. 



certain proportion pa&sea tlirougli without parting with ite 
oxygou, a fact winch has also been deinonsT rated by aniily&is^ 
aad consequently retaina its red color. The explanation in 
cases of syncope is probably the same; tliongh thin is merely 
a supposition. Even diit'ing secretion, a certain q^iMitity ot* 
uarbouic acid is formed in the gland, wliicb, according to 
Bernard, h carried off in solution in the eocreted £uid.' 

It may bo stated in general terms that the color of the 
blood in tbc arteriea ia bright red : and in tLe ordinary veins, 
like the cutitneous or miiacular, it is dark blue, almost black. 
It is red in the veins coming from glandii during secretion, and 
dark during the intervals of secretion. 



Anatomical Eievienta of the Blood. 

In 1&61, the celebrated anatomist, Halpigbi, in examining 
the blood ot" the hedgehog witli the feeble and imperfect 
lenses at his conunaud, discovered little floating particles 
which he mistook for grnnulea of fat. but which were the 
blood-eorpuscles. He did not extend bifi observationB in 
this direction; but a few years later (1673)^ Leenwen- 
boek, by the aid of pimple lensea of bis own construction^ 
varying in magniiying power from 40 to 160 diameters, first 
saw the corpuscles of human blood, which he minutely 
described in a paper pnbliafied in the Pliilosophical Trans- 
actions, in 16TJ-. To hira is generally ascrJl'ied the honor of 
the discovery of the blood^orpuaclo?. About a century later, 
"Williatu Ilewson' described another kind of corpuaclea in 
the blood, which are inucti less abundant than the red, and 
which are now known under the name of white globules, or 
as they have lately been called by Robin, leucocytes. 

Without following the progre^ of microscopic inveetiga- 

' Bernakh, op, fit,, inxaii i., p. 34*. 

* Tbc 'Works »i WilLiam Hs^vftoUt V. It S., ^dniluim Society edicLoD, Loadon, 
IBi6, 



ABATOMICAI. ELKMEKl^. 



109 



Huns into the oonatitation of tLe blood, it may l>e Elated 
that it is now known to Iio compo&ed of a clear fluid, ilie 
Pia^ma^ or liquor aan^guinU, UoltHng certain eoqiiieelea iu 
guspotiaion. These corpnselcs are 

1. J^ed Corptrndes ; by for the mo&t abundant, constitutinf^ 
about one-half of tiie ujaas of blood. 

9. Zeu4}f}ei/tss, or Whiie Co-rpuscles ; much leee abundant, 
existing- only in tbe proportiou of one to several hundfied red 
corpudL'les. 

3. Oranid^s; exceedingly minute, called, by Milne- 
Edwards, globnlina, and by Kiilliker, elementary grwinlea. 
Those are few in number, and areunJouhtedly fatty particles 
from tbe ehyle. Tliey ure to be regarded as accidental eon- 
Btituents of the blood. 

Red Cftrpmdfs. — These little bodies give to the blood its 
red color and tte. opacity, Tbey ace tnie organised etructurea, 
Containing organic iiitrogeuized and inorganic elements moleo- 
ularly united, and, ma au exception to tbe general rule, a lit- 
tle fatty matter in union with tbeir urganic principle. Like 
other organized etruetuiTS, they are constantly undergoing 
decay, and are capable of aeli-regeueration. They coiifititute 
about one-haU' the mass of blood, and, according to the obBer- 
vfltions of all who have iuvCTtigated this aubject, are more 
abundant iu the umie than in tlie female; this constituting, 
perhaps, the only constant difference in the coniposltlon of 

blood in the ecKes. 

The form of the blood-corpuscles is peculiar. They are 
flattened, bi-coneave, circular disks, -with a thickness of froin 
one-fourth to one-tliird of their diameter. Their edges hjc 
rounded, and the thin central portion occupies about one-half 
of their diameter. Their conBistence is not much greater 
than that of tbe plasma. Tliey are very elastic, jind if de- 
formed by pressure, immediately resume theu* original shape 
when tbo prcGsure is removed. Their specific gravity u 
from 1C>8S to 1105. 



110 



THE BLOOD. 



Tlie peculiar form of the blood-eorposdea gire& them a 
very characteriBtie sppearaace under tlie ir)i(:j-oecop<?, "WTien 
exaniiiieJ with a magnifying power of from 300 to 500 
(Jiametera, those whicli preacBt their flat sui'faces have a 
ahiidcd centre, when the edg;es are in focus. Before we were 
in posaeasion of the perfect instruments now used in micro- 
sco]>ic investigation, this spot was snpi>08ed to be a nudeuB 
having a constitution dift'erenL from the rest of the porirascle. 
Now thii is nnderstood to be an optical effect, the result of 
the form of the corpu&cle; their bi-eoncavity rendering it im- 
possible for the centre and edges to be exac-tly in foc-og at 
the same instant, &o that when the edgc^ are in. focus the 
centre is dark, and when the centre is bright the edges are 
shaded. 

Afi the blood-corpuscles are examined by the microscope 
by transmitted Hglit, they are quite transparent, and of a 
pale amber color. It ia only when they are collected in 
raaBsee that they present the red tint cliaracf eristic of blood 
as it appears to the naked eye. This yellow or amber tint ia 
characteristic A pretty good idea of it may be obtained by 
largely diluting blood in a tost tul>e and holding it between 
the eye and the light. 

In examining blood under tbe microscope, the corpusdee 
are seen in many different positions ; some flat, some on their 
edges, otc. This assiets us in re<wgiiiziug their peculiar 
Ibrrn. 

It baa been observed by microacopiats that the blood- 
corpuscleBbave a remarkable tendency to arrange themselves 
in rows Uke r&ulfiadtx of coin. This haa attracted univerBftl 
attention, and for a long time was Dot eatisfactorily explained. 
Robin has lately given iia what seems to he the true explana- 
tion of this phenomenon.' This observer has shown that 



iitirH/CM dn •'^njF. — Jovriiat da la Fhifti'iiogit tk tHomtne el tin ^nfifuttU, 
Pacla, ISAS, tome L, p. SQS. 



KED COIlPrSCLEfl, 



in 



sLortly after removal from tbe veBeela, there eitidea from tlia 
oorpuddts i\u. adliesivB aubstance wliieli emeaJB their eurface 
and causes ttiem to Btick together. Of course the tendencj 
is to adhere by their flat eTirface&. In examining a specimen 
of blood under the niier(«icopc, the presence of this adheaive 
exudation may be dcraonatrateil by employing- firm and, 
gradual pressure on the glass cover, when the adherent cor- 
pu^Ies may be separated in some instancea, and with oblique 
lig-ht we can Gometiines see a little transparent filament b&- 
tveen them, -which draws them together, as it were, M-heu 
the pressure ts removed. This phenomenon ia due to a post- 
mortem change, hut it owurs so aoon, thnt it prcsenta itself 
in nearly eyery speciuien ofj'reali blood which we examine, 
aod is therefore mentioned in conuuction with the normal 
ch&nicters of the blood-corpuscles. 

Dinum^wng. — Tlie diameter of the hlood-corpuacles has 
A more than ordinary anatomical icitercst ; for, Viirying per- 
haps lees in size than other anatomical elements, they nm 
rather taken as the standard by which we form an idea of the 
Hize of other microscopic objects. T!iq diameter usually given, 
is jjVit of fti* inch. The exact meaanreraeut givon by Robin 
is .0i'T3 of a millimeter' or ^^^ of an inch. It is stated by 
some authors that the size of the corpuscles is very variable, 
even in a single specimien of blood. We havo repeatedly 
nipfiiinred them with the eyfrpiece micrometer of TCachet, 
and found a diameter of jj's7 O'f an inch. Very few are to 
Iw found which vary from this measurement, Kolliker, who 
giveft their average diameter aa ^j-^s 0^ ^^ inch, states that 
" at least nittety-tive out of evei^ hundred corpuBcles are of 
the same size."' 

We cannot leave the subject of t!ie size of the blood-cor- 
puscles witliout a notice of the tncat^m'ementa in the blood <^f 



*lM. eit 

' ROLLiun, Slatiiutta/ Mii^Mfi^e Analsiitji, LonUon, 18G0, p. CID. 



113 TH£ BLOOD. 

different animals. This point is interesting from the fact 
that it is often an important question to determine whether a 
given specimen of blood be from the human subject or one 
of the inferior animals. Gomparative measurements also 
have an interest on account of a relation which Beema to 
exist in the animal scale between the size of the blood-cor^ 
puscles, and muscular activity. In all the mammalia, w^ith 
the exception of the camel and llama, in which thej are oval, 
the blood-corpuscles have the same anatomical characters as 
in the human subject ; the only difference is in size. In only 
two animals, the elephant and sloth, are they larger than in 
man ; in all others they are smaller, or of nearly the same 
diameter. By reference to the table it will be seen, that in 
some animals tlie corpuscles are very much smaller than in 
man ; and by accurate measurement, we are enabled to dis- 
tinguish their blood fromr the blood of the human subject. 
But in forming an opinion on this subject, it must be remem- 
bered that there is some variation in the size of the corpusclee 
of the same animal. We can easily distinguish the blood of 
the human subject, or of the mammals generally, frvm that 
of birds, fishes, or reptiles ; for in these classes of animals the 
cor]>uscles are oval and contain a granular nucleus. 

Milue-Edwards has attempted to show, by a comparison 
of the diameter of the blood-corpuscles in different species, 
that their dimensions are in inverse ratio to the muscular 
activity of the animal.' Reference to the table will show 
that this relation holds good to a certain extent, while there 
certainly exists none between the size of the corpuscle and 
the size of the animal. In deer, which are remarkable for 
their muscular activity, the corpuscles are very small, ttVt 
of an inch; while in the sloth they are tiVjd ^"*i ^^ tl^s ape, 
which is comparatively inactive, ajffs- But, on the other 
hand, in the dog, whicli is quite active, we have a corpuscle 



' Miute-Edwardb^ Zefmi tur la Phytiologie et VAiMlComie Comparte^ 
tome i, p. 57 tt itq. 



— irrTT-at- T TS , 



112 



acETT". the iiazuMa- :i 3^ .s:-rpngi^ s sj-j, of sn zum. 

iZii TiTyw':^-' Ji^'rf^j s 3«7C iiT^izfabiie. fc s eaom due dte 
Fi-^yr t^r -v» ^ h. ^si* zTQU dtasHS ocT w^aK cne aoukJor the 

•:f£i??« I'tf T^dJes. iz>i die anaZesc ia. 'die zuumnal^ la. =te 




WB7«i. Ic v^ » inasnai t&ac ^ thwiuar -if dw nmaL "iiuii iuijimji 
fsBHT "tun. ^1^ [11— J -» iifligi. ^ aiiK M s^BB ji aomi 'Jik d. Aos nv 

"^D^DiOflt VB ^^** ^DB^^SS^DShC^B V 3^E H IVES ^D^^ IBS 

'^iarinf if ~iit* 'Hjijiui^iefl in fiflb^nc t" filter ^f i nsodnc 

■iu liimii if 'iie innuK mpiRa ftna 4k if mmc « ±a !iifaja t~— -> 

K niRSiiui -vtiien. s id^ if Mai JBumuee. Thti m ■mii 1 im urn ^ iJ. 

■J'iiA """■«■"» jAvii MBL »ii'f i"iTyf •'IT 4e TKzatiaiL ininin i' "— ji^fis 



Kbl. ■ 







5ttat 



nr% 






'.•5 1 '^rof i.. 5. Wtj. £j siM urxi» It. Biiinc sbh * nmu^ if 3r"=V!nrint 
mima^ n. -jrt :u.<vi if v^iiiiB j« has iiaiui airnamuR tt F««w» . Tim it id 
Vi*^-L "u -i* pa^ru jina, 3ac kejomJcs fxiic 11117 -" ^* liuM -if '3* ■'•ax. 



lU 



THE BLOOD. 



Bat, 

Long-eared Bat, 
Mole, . 
Hedgehog, 



Polar Bear, 

Brown Bear of Europe, 

Black Bear of K. America, 

Bacoon, 

Dog, . . . . 

Fox, .... 

Jackal, 

Wol^ .... 

Striped Hyena, . 

Spotted Hyena, 

Oat, . 

Lion, .... 

Tiger, . . . 

Leopard, 

Pnntber, . 

Ferret, .... 

Weasel, 

Polecat, 

Ottw, 



Seal, . 
Porpoiae, 



J>Um«ter, 
n^ 

irnr 

ITTT 
TTTt 

TTmr 

■HTKT 

1 
TTTT 

T^ 

Wrv 

T^, 

TTffT 

Witt 

JTTf 

n^ 
TrSnr 
TTVJ 

tM 

TTIfT 



Giraffe, . 
Antelope, 
Gazelle, . 
Goat, . 
Sheep, 
Ox, . 
Buffalo, . 
Mnsk Deer of Java, 
Flying Sqnirrel, 
Bed Squirrel, 
Black Squirrel, 
Gray Squirrel, 
Marmot, . 
Brown Kat, . 
Black Bat, 
Mouse, . 
Water Rat, 
Porcupine, . 
Beaver, 
Guinea Fig, , 
Babbit, . 
Two-tood Sloth, 
OpoHSUin, 
Kangaroo, 



TjigT Dromedary (oval), 
,Xt Camel (oval), 



Dbmetar. 
ITTT 

31^ 
T^ 

TTTfT 

Wry 

nfrr 

'in 9 

J^ 

nVr 

iVrr 
nW 
t.Vt 

tVtt 

I., dlun. 8. diKD. 

rnri ttti 



Birds. 



CoTputdet OvaJ. 



Eagle (ring-tail 

Owl, 

Jay, . 

Raven, 

Starling, 

Wren, . 

Sparrow, 

Woodpecker, 

Swallow, 

Stork, . 



ed 



DUmeter. 

• ThSr 
TTTT 

- 8T?rr 
tAt 

• 51 Iff 
yA-j 

• BlVv 

• n'.T 

Wry 



Bhort 
Dlamuter. 

i-Aff 
tAt 

yiViF 

jAff 



Pigeon, 
Turtle-dove, 
Peacock, . 
Cock, . 
Turkey, 
Guinea-fowl, 
Quml, 
Goose, . 
Swan, 
Duok, . 



DIun'r. 
tAt 
tAt 
tAt 
rnrr 
iAt 
iVjt 
bAtt 

1 A t 

tAt 
tAt 



BbrH 

DIui'r. 

) At 
1^ 

I As 

>At 
sArf 





BED COEPUSCLES. 




HepiUea. 




Corpuidet Oval, 




Low Bboit 
DUm'r. JXuD'r. 


Qreen tmtle, . 


• lAr tAt Lizard, 




• • -rVfi nSr Viper, 




Amphibia. 




CorpuacU* Oval. 




Lonf Short 
DlMnr. DUm'r. 


Frog, . . 


. ttVt tiVt Toad, 




Fishes. 




Corpmcles Oval. 




Low Short 
DIhbY Dlun'r. 


Perch, 


■ ¥^ tAi Pike, 


Carp, , 


TT-fT T^ Eel, . 



115 



ODf 

]>km>. Dtrun'r 



Loiw Short 
Dlam'r. DUin'r 



mW 



Low Short 
Dlun'r. DUm'r. 

nmF IT5T 



Miumeration of the BloodrCorpitscles. — ^la most of the 
quantitative BDalyses of the blood, the proportion of moist 
corpuscles to the entire mass of blood is stated to be a little 
less than one-half. This estimate is necessarily rather rough ; 
and it wonld be interesting to ascertain, if possible, the nor- 
mal Tariations in the proportion of corpuscles, under differ- 
ent conditions of the system, particularly as these bodies play 
80 important a part in certain of the functions of the organ- 
ism. Estimates of this kind have lately been made by Ma- 
lassez,* who has devised a method, more accurate than tbose 
employed before, for the actual enumeration of the red cor- 
puscles, in which, it is stated, the error does not amount 
to more than two or three per cent. The process employed 
is the following : 

The blood to be examined is diluted with ninety-nine 
parts of a liquid composed of one volume of a solution of 

' Hu^isBKZ, NouveUe milhode de nnmfralion den ^hitmlei rougtt et dfs globviet 
Vnum du tanff. — AreMva de phyttolagie, Paris, 1874, tome Ti., p, 32, ei uq. 



116 



THE BLOOD. 



guni-nrahic of ei specific gravity of 1020 with tWee volumes 
of a solution of equal parts of sulphate of soda aud chloride 
of Bodiuin, also of a epcL-ific gravity of 10'2O. The mixture, 
containing one part of blood iu one himdred, is introduced 
into a small thermometer-tube with an elliptical bore, the 
eides of the tube being ground flat for convenience of nii- 
eroecopical exainination. The capacity of the tube is to be 
caiculntod, by eetiniating the weight of a volume of merc-ory 
contained iu a certain length. The tuba is then tilled with 
the diluted blood, and the number of corpust-IcB in a given 
length of tlic tube is counted by uieane of a niicroecope fitted 
with an eye-piece micrometer. In this way, the unniber of 
porpnsclcs in a given volume of blood can be readily esti- 
mated. In man^ the numbL>r in a cubic nullimeter of blood 
(a millimeter — about ^ of an inch) Is estimated at about 
four million. 

According to the observations of Malnssez, the propor- 
tion of eorjiusele* U abont the fi.inie in all parts of the arte- 
rial system. In the vclnB, the corpuEclcs arc more sbuudant 
thitn in tlie urteries. In the venous system, the blood of 
the aplenic veins is found to posscea the largest proportion 
of corpusclee, and the proportion is Bmallest in the blood of 
the hepatic veins. These rcsnlts favor the idea that the red 
corpuscles are funned, to some extent, in the spleen, and 
that n number are destroyed in the liver; but farther obser- 
vations are necessary to render this view certain. 

Post-woriem Changen in the J^I'Ood-Ca}'j?tiades. — In es- 
aniining tlie fresh btood under the niieroscopc^ after the 
Bpeeimcu has been under observatiion a short time, the cor- 
puaclea Basumea peculiar appearance, from the development, 
on their surface, of very minute, rounded projections, like 
tho granulea of a raspberry; indeed, they are said by the 
French to become fi^amhohef^ which expresses the appear- 
ance vcrj- well. A little later, when they have become 
partly desiccated, tbej present a shrunken, appearance, and 



BED OOBPTTSOLBe. 



117 



their edges are more or loss Berrated. tTncler tliesc cir- 
cumstances, their original torw tufty be feslored by fldding 
to tlie specimen a liquid ut' about tiie density of the blthuu 
When they have been completely (Iricd, as in blood spilled 
opon clothing or r floorj niontha or even years at'tijr, they 
can be made to nsBiiniii their characteristic iorni by being 
eareftilly moistened with an appropriate liquid. This prop- 
erty IS tuken advants^e of in esaniiiiatioTis of old spots siip- 
jwsed to be blood; and, if the manipulations bo carefully 
conductetl, the corpuscles may be recognized without diffi- 
culty by the inicroEcope.' 

If pure water be added to a Bpecimen of hlood under the 
microsccpG, the corpuscles swell up, become Bpherical, and 
are finally lost to view by solntion. The same etfect follows 
almost instantaneously on the addition of acetic acid. 

SHrucfwe, — The strueture of the blood-corpuscles ie very 
fiiiiiple. Thuy are perfectly honioge] icons, presenting, in 
their nomifl] condition, no nuclei or granules, and are not 
provided with an investingraenihr.ine. A great deal has been 
said by anatomists concerning this latter point; and some 
are of the opinion that they are cellular in their structtire, 
Composed of a mcmbratiCj with viscid, eeniifluid contents^ 
Without going fully into the diBc'ussjon of this qneetion, 
it nay he stated that few have assnnied to have actually 
demonstrated tbiB membrane; but certain obscr vers have in- 
ferred ite existence from the fact of their swelling, and, as 
they term it, bursting on the addition of water. The ap- 
pearances preeetitcd upon the addition of iodine to blood pre- 
viously treated with water, which have been supposed to 
indicate the preeenee of shreds of ruptured vesicles, are not 
BufRciently distinct to demonstrate the existence of a mem- 
brane. The great elasticity of the eorpuBcles, the persifit- 

• Fer full diwclionft for the eiam[u«tlon of blood^taiM, the reader ib re- 
f»nv4] to aa Article on tlm nn^ii^D-lcg-nl eiKiuiDniion of spots of bln-oil by Robin^ 
putiliihud ID (lie^ Buffi^n ittdkal Jounuit, 1887— 'QB, toL lili,, p. 665, ft aij. 



lis 



THB SLOOD. 



enoQ with which they preserve their biconcave form, and 
their g^oiieral appennmce, mthei' fav._>r the idea thnt they are 
Lcmioge neons hodlcs of ft detinitc shape, thim thut thev have 
a cell-wall with semifluid content b ; cspecialtj as the exist- 
ence of a memlirane hae btien oii\y inferred and not posi- 
tively demo n&trti ted. Their mode of nutrition is like that 
of any other anatomical elements. They are contimuilly 
bathed in a nutritivi3 fluid, the plasma, and, a& fast as. their 
suhfltance becomes worn out and effete, new material is 
stipjilted. In this way, they undergo the same raolei'iilar 
ch^iifres as other auatumicnl elementg. When de^ti-oyed, or 
removed from the body in Liejnoi'rhagee, tievv* corpuscles are 
grtidually developed, tiotil their q^uautity reaches the normal 
Etandard. 

Devdcpmetit of the B}ood-Co}'pii€cUg. — Very early in the 
development of the ovnin, the blood-veseels appear, consti- 
tutinLT wliat is cflHtd the area vasculosa. At about the 
eenie time, the blood-corpusetes are developed, it may be 
before, or it may be just after the appeamnco of tlic vessole, 
for this point is undetermined. The blood hecoinefi red 
when the embryoQ ia about one-teiitli of an inch m length. 
From tliis time until the end of the Gixth or eig^lith week, 
they are from thirty to one hundred per eent. larger than in 
the adult. MoBt of them are tdrenlar, but $ome are ovoid, 
and a few are gUibular. At this period, nearly all of them 
are pi'ovided with a nucleue; hut, from the first, there are 
some in which this is wanting. The nuclcnB is from -"uVtr 
to fl-n'jur of an inch in diameter, globular, gramihir. and in- 
Boliible in water and aeetle acid. As development adv.^neee, 
Ihese nucleated corpuscles are gradually lost ; but, even atJ 
the fourth month, we may still see a few remaining. Aftci 
this time, they present no anatomical difl'erenccs from thJ 
blood-corpupcles In the adult. 

In many works on phyaiology and genenil anatomy^ 
find accounts of the development of the red corjtoscles ¥■» 



I 



BED COEPC8CLE3. 119 

the colorless coTpuBcloSj or leucocytes, wliich nre BTipposed 
to become disintegrated, their particles being developed into 
red corpuscles ; but there seems to be no positive evidence 
that such a process takes place. The red corpuscles ap- 
pear before the leucocytes are formed ; and it is only the 
fact that the two varieties coexist in the blood-vessels which 
has given rise to such a theory. It is more reasonable to 
suppose that the red corpuscles arc formed by a true genesis 
in the sanguineous blastema. We can o£fer no satisfactory 
explanation of the process by which the anatomical elements 
of the tissues are formed, nor can we explain the way in 
which the blood-corpusclesj which are true anatomical ele- 
ments, take their origin. There is, fiirthermore, no suf- 
ficient evidence that any particular organ or organs have the 
function of producing the blood-corpusclea. It is regarded 
by some as a necessity that there should be an organ for the 
destruction of the corpuscles, and one for their formation. 
Kegarding them, as we certainly must, as organized bodies 
which are essential anatomical elements of the blood, it is 
difficult to imagine what reasons, based on their function, 
should lead physiologists to seek so persistently after an 
organ for their destruction. The hypothesis that they are 
used in the formation of pigmentary- matter seems hardly 
sufficient to accoimt for this. The observations of Malassez, 
which show an increase in the number of corpuscles in the 
blood coming from the spleen, and a diminution in the blood 
of the hepatic veins, are not sufficiently definite to serv-c as 
a demonstration that the spleen is a blood-forming organ ; 
and the same reinark applies to observations U]X)n the for- 
mation of blood-corpuscles by the marrow of the bones. 

In the present state of our knowledge, the following seem 
to be the moet rational views with regard to the develop- 
ment and nutrition of the blood -corpuscles : 

1. At their first appearance in the ovum, they are formed 
by no special organs, for no special organs exist at that time, 
but appear by genesis in the sanguineous blastema. 



120 



THE BLOOD. 



2, 'WbcTi f-oWy formed, thcj flro i-egulfLvly-orgaaized ana- 
tomical eleiiiente, subjuct to the same laws ofgraditiil iiiuluc- 
iilai* waste and repair as any of the itnatomicul elements of 
the tissues. 

3. Tiiev ai-e o^enerated tie nm'o in the adult^ when dimin- 
ished in quantity by liiemorrhage or otherwiee, and, nnder 
these circunist antes, they arc probably Conned in the liquor 
sanguini'fi, by the same process by whkh tlicy take thqir origin 
in the ovum. 



Functions of the Blood-Corpuscles. — Although the albumi- 
noid constitueDte of the plasma of the blood are epsential to 
nutrition^ the red eoiiiiiBctes arc the parts most immcdinTcIy 
necessary to lite. We have already seen, in treating of traus- 
fufiion, that life may be I'esEored to an animal in which the 
functions have been Bu&pendedfroni htemorrhage, by the in- 
Irodiititioa of fresh blood ; and, while it is not nccessarj- that 
this blood should contain fibrin, it bus been shown by the 
experiments of Provost and Dumas and othere, that the 
intPodiH'tion of serum, without the corpueeles, has no resto- 
rative etfect. When all the arteries leadin^r to a ]irirt are 
tied, the tisaues lose their properties of eontraetility, sen- 
sibility, etc.j which may be restored, however, by supplying 
it again with the vivifying fluid. We Bhall eee, when we 
cjme to treat of the function of respiration, that one great 
distinct luu between the corpuscular and £uid Blemcnls of the 
blood is the great e-apaeity which the former have forabsorb- 
i\\^ p;ases. Direct observations have shown that blood will 
absorb from ten to thirteen times as nmch oxygen as an equal 
hulk of water^ and this is dependent alnmst entirely on the 
presence of the red corpuscles. As the tissues are constantly 
ahsurliing oxygen and giving off carbonic acid, a very im- 
portant function of the cori>uscle3 is to cariy oxygen to all 
parta of the body. In the present state of our knowledge, 
this is the oidy well-defined I'unetion wliich can be attributed 
to the red corpueeles, and it imdunbtedJy m ihe principal one. 



LEL'CXJCYTES, OB WniTE COlilTSCI-ES. 121 

Tbey have an aftinity, ttongh not so great, for carbonic acid, 
vhich, after tbe blood has circulated in the capillaries of the 
■ystem, bikes the place of the oxygen. In Bome experiments 
performed a few years ago on the cfTects of hemorrhage and 
the aeat of the "heaoin de resptrer" we demonstrated that 
one of the results of removal of blood from the system was 
a condition of asphyxia, dependent ujran the absence of 
these respiratory organs. The following may, therefore, be 
stated as the principal fnnction of the red corpuscles of the 
blood: 

They are respiratory organs, taking np the greatest part 
of the oxygen which is absorbed by the blood in its passage 
through the lungs, and conveying it to the tissues. 

IJgucoci/teSj or White Corpuscles of t/ie Blood. — In addition 

to the red corpuscles of the blood, this fluid always contains 

A number of colorless bodies, globular in form, in the sub- 

itance of which are embedded a greater or less number of 

minnte granules. Thesehave been called by Hobin, leucocytes. 

This name seems more appropriate than that of white or 

eolprless blood-corpuscles, inasmuch as they arc not peculiar 

to the blood, but are found in the lymph, chyle, pus, and 

Tarious other fluids, in which they were fonnerly known by 

£fFerent names. All who have been in the habit) of cxam- 

uung the animal fluids microi^copically have noticed the 

gmt similarity between the cor^iuscular elements found in 

tts above-mentioned situations; and, na microscopes have 

hetn improved and investigations have become more exact, 

^Tirieties of corpuscles have been narrowed dowii. It is 

nowpretty-generally acknowledged that the corpuscles found 

in nitcaB and pus are identical ; also, that there is no differ-' 

•Welietween the white corpuscles foimd in the lymph, chyle, 

md Uood ; and, finally, it has been shown tliat all of these 

l*fiei, which were formerly supposed to jiresont marked 

wi^Dctive characters, belong to the same class, presenting 

bntdi^t differences in different situations. The descrip- 



i 



123 



THE BLOOD. 



tiijii wliich will Ije giveu of the white corpuscles of the blood, 
ami Ihe etfecte uf reageuU, will auBWer, iu the raiiin, I'or bU 
tlio porpuscular bodies that ara grouped under the Dume uf 
leucocytes,' 

Lelleoe^'■tes are normally found in the blood, lymph, 
cIiyIl', semen, colostrum, and vltreouB bitmor. PatUuIog-i- 
cally, they are foniid in the secretion of mueons membranes, 
following irritation, and in indammatury produel^s, when 
tliey arc called piis-corpuacles. 

In examining: a spccuuen of blood with the microscope, 
we inimedijitely notice the marked difference between the 
lencocyteB and red corpuscles. The former are globular, 
with a smooth Burl'ace, but rendered eoraewhat opaque by 
the presence of nioro or kss gratmlar matter, white, and 
larger than the red corpuscles. 

In examining the circulation under the microecope, we 
arc struck with the ndlieeive character of the lencneytee ns 
compared with the red cori^>HPclc8. The latter circuhitu with 
great rapidity in the centre of the veseela, while the leuco- 
cytes have a tendency to adhere to the Bides, moving along 
slowly, aud occasionallj- remaining for a time entirely sta- 
tionary, until they are swept along by a change in the di- 
rectiou OF force of the current. 

Their e.ize varies somewhat, even in any one fluid, each 
aa the blood. Their avern<fc diameter may be staled aa 
yg^ i f of an inch. It ia in pns, where they exist in greatest 
abundance, that their microBcupieal characters may he stuJied 
with greatest advwnfeige. In this fluid, ai'ter it ib discharged, 
the corpuscles somctimcB present remarkable deformities, 
They become polygonal in shape, and sonietunes ovoid, oa- 
casionally presenting projectiona from their surface, which 
give them a stellate appearance. These alterations, bow- 
ever, are only temporary ; and, sflcr from twelve to twenty- 

' Fora fal! account o^CilioBniLtoniy&rjil plijaiolo^ of these bodice, tk« nadcr 
ts nfvmd to an (.'lattorate anicle b^ lEoblu^ in the JoitmeU it la^^gtiat^lat 
FEril, lSfr9, tOEM U., p. 41, II Kq. 



LEUOOCTTEB, OR 'WHITE CORPF8CLES. 128 

four hours, tliey resume tlieir globular shape. On the addi- 
tion of acetic acid, they swell up, become transparent, with a 
delicate outline, and present in tlieir interior one, t«o, three, 
or even four rounded, nuclear bodies, generally collet-ted in 
M mass. This is rather to be considered as a coagulation of 
a portion of the corpuscle, than a nucleus brought out by 
the action of the acid, which renders tlie eorjmscle traiis]»ar- 
ent; though in some it is seen through the granules without 
the addition of any reagent. This appoai-ance is produeeil, 
though more slowly, by the addition of water. 

Leucocytes vary considerably in their extemal characters 

in different situations. Sometimes they are very pale and 

almost without granulatiouB, while at others tlicy arc titled 

with fatty granules and are not rendered clear by acetic 

Knd. As a rule, they increase in size and become granular 

when confined in the tissues. In colostnim,' wlien they are 

called colostrum-corpuscles, they generally undergo this 

change. As the result of inflammatory action, wIk'u they 

ue sometimes called inflammatory or exudation-corput>etes, 

leucocytes frequently become much bypertropbied, and are 

filled with fatty granules. 

The deformation of the leucocytes, to wliich allusion has 
ibody been made, is sometunes so rapid and changeable as 
to produce creeping movements, due to the projection and 
Rtnetion of portions of their substance. These movements 
tteof the kind called amoeboid, and are supposed to be im- 
portant in the process of migration of the eorjmseles, which 
I'M Ittely been described. This question, however, has more 
<^i pathological than a physiological interest. 

* Oolortnim is the dUcfaargc from the miimmary fflnnds, nrciirriDf! iluring 
'•Sntfcw iUy« »ftcr d^liverr, wliii-Ii iircci-Jw the full estubliiihim'iit of the 
'•'•■I •ecratlon. It Is a st-nms fluid, rather t-Irar. which iirt-sciit:', on mioro- 
Mqikil eumination, K few milk-glolmlc^, larf^c (lr(i]iH of oil, munJi-il manned of 
"^ btt; grftDnlei, utd enUi^ed and granular Icueocytrfi, calh'd (.-iilor'tnini- 
ll*|Mi1ai, u well u those which haro undergone no altcratiim. Thrive gnuhi- 
""rilhunwi, u t^ aeontion is esubliiihed, and their place i^ sujiiilicd bj the 



124 TnK BLOOD. 

The quantity of leucocytes compared to the red corpus- 
cloE can only be given approximately. It lias been estimated 
by counting under the microscope the red corpuscles and 
leucocytes contained in a certain space. Moleechott gives 
the proportion as 1 : 335 ; others, at from 1 : 300 to 1 : 500. 
It has been found by Dr. E. Hirt, of Zittau, whose obser- 
vations have been confirmed by others, that the relative 
quantity of leucocytes is much increased during digestion. 
He found, in one individual, a proportion of 1 : 180(1 before 
breakfast ; an hour after breakfast, which was taken at S 
o'clock, 1 : 700 ; between 11 and 1 o'clock, 1 : 1500; after 
dining, at 1 o'clock, 1 : 400 ; two hours after, 1 : 1475 ; after 
supper, at 8 p. m., 1 : 550 ; at llj p. m., 1 : 12ii0.' The 
leucocytes are much lighter than the red cori:iu6C'le6, and, 
when the blood coagulates slowly, are frequently found, with 
a certain amount of colorless fibrin, forming a layer on the 
surface of the clot, which is called the " bufly-coat." Their 
specific gravity is about 1070. 

!NumerouB obser\'ers, among whom may be mentioned 
Donn6, KoUiker, Gray, Hirt,' and Malassez,* have noticed a 
great increase in the number of leucocytes in the blood 
coming from the spleen, and have supposed that they are 
chiefly manufactured in this organ. It is inconsistent with 
the mode of development of these corpuscles to suppose that 
any special organ is exclusively ^;ngaged in their production ; 
and their persistence in animals after extirpation of the 
spleen shows that they are developed in other situations. 

The fiinctjon of the leucocytes is not understood. The 
supposition that they break down and become nuclei for the 
development of red corpuscles, which at one time obtained, 
and is now adopted by some writers, is a pure hypothesis, 
and has no positive basis in fact. 

• Milke-Edwaxds, Zefotu tvr la phytiologit. Fans, 1867, tome i., p. 860L 
' IbiJ., p. 3S3. 

* Malabsez, Novvdie miOiodt de numtration daglolttda igtuga tl dc globvlet 
blanet du tang. — Arehivet dt phgiidogit, P&ri«, 167i, tome vi, p. 82, tl teq. 



LECC0CTTK5, OH WUITi: CX>KPfSCLKS. 125 

Development of Leucocytes. — These coriniseles ajipear in 
the blood-vesselB very early in fcetal life, before the lympliat- 
ic8 can be demonEtrated. They arise in the suiiie way as 
the red corpuscles, by genesis from materials existing in the 
Teasels. They appear in lymphatics, before these vessels 
paes through the lymphatic glands, in the foetus, anterior 
to the development of the spleen, and also on the surface of 
mncons membranes ; so tliey cannot be considered as pro- 
duced ezchisivcly by the lymphatic glands, as lias been sti^v 
posed. Tliere is no organ or cla^s of organs in the body 
ipeciaTly charged with their formation ; ami, altliuugli they 
frequently appear as a result of inflammation, tliis process 
it by no means necessary for their production. Ilobin has 
cuefnlly noted the phenomena of their development in re- 
cent wounds.' Tlie fii^t exudation consists of clear fluid, 
»ith a few red corpuscles ; tlien, a finely granular blastema. 
In from a qxiarter of an hour to an hour, pale, transparent 
^bnles, from -g^-^ to ^-jVir ^^ ^^ ^^^^^ '" diameter, make 
tiieir appearance, which soon become finely granular and 
present the ordinary appearance of leucocytes. They are 
thu developed, like other anatomical elements, by organiza- 
tioii of the necessary elements furnished by a blastema, and 
Hot \sj the action of any special organ or organs. 

This view of the mode of development of leucocytes 
•oema to be established by the following verj- elegant ex- 
periments of Onimufi, sliowing that corpuscles may he de- 
*Bloped, under fevorable conditions, in a perfectly clear, 
wxxK^neona blastema : * 

OnimuB used the clear fluid taken without delay from 
'■picDy-developed blisters, which he found onlinarily eon- 
*'i>ied no leucocytes, but which he carefully filtered in order 
to vcmoTe all sources of error. The tillered liquid contained 

BoBOr, Air qn^quu pninlt de ranaiittuie et dr la pii/iii'ilcpiE dm Ifuaici/tti.— 

it Im phjfriotogit, Tim», 18S9, tomt' il, p. .15. 
OiniDI, Stf>tntnf€i tmr la gmi*t dn Itvcwi/te* el nur fa phit:r<Jlhn *pnnl<int«, 
d* rcMtairf* ** dt la pht/$iologit, Paria, ISBT, tome iv,, p. 47, rt vq, 
9 



12G 



THE BLCM>n. 



no morpliological elements ; "butj on tho otlicr liand, ba 
found that, if the liquid were alltiwed to rennaiu ft>r an hour 
or moi-e in contact -with the ili;nii», it always coataioecl leu- 
cocytes and epithelial cclli. Uutler tliese circumstimces, 
even after fiJtratiun, the liquid contained a few leucocytes ; 
but, after eix or seven LourB of repose in a conioaJ vessel, 
the corpuscular elenientB griiviiated to the bottom, leaving 
the upper portion of the liquid perlcotly clear. 

This liquid, entirely free from anatomical elcmentB, was 
enclosed in little sacs formed of an animal membrane (gold- 
heater's sliin) and introduced under the stin of a linng rab- 
bit. At the end of twelve hours, a few small loucocytee 
aqd grauulcitlona had made their appearance ; at the end 
of twenty-four honrs, the Huid Lad become somewhat opaque, 
and contained a large number of leucocyteB and granula- 
tiona ; and, at the end of tbii'ty-elx hours, the fluid wae 
white, niillij, and compoeed almo&t entirely of leucocytes 
and granulations. The leucocytes, which were exiimined 
also by Prof. Robin, presented all the charactera by whicb 
these corpuscles are ordinarily recognized. These experi- 
ments were repeated with more thau forty difl'ereut Bpeci- 
niens of fluid from blietere. 

The experiments wore then varied in oi"der to show the 
influence of the membrane and of the coniposition of the 
blastema upon the development of leucocytes. By modify- 
ing the membrane iu which the blastema was enclosed, it . 
was found that the corpuscles were rapidly developed in 
proportion to the activity of the osmotic action. When 
thick animal membranes were used, their development was 
slow, tind, in some instances, did not take place at all. There 
was no development of leucocytes in a clear blastema en- 
closed in a sue of caoutchouc or In glass tubea hemietjcallj 
scaled ; and from this it was concluded that osmotic action 
Is a necessary condition, and that tiie mere heat of the body 
is not siLffiiient to develop thceo corpuscles, even iu an ap- 
propriate blastema. The influence of this constant molecular 



ELEMENTART COBnJBCLlM. 



moTement is in striking contrast to tlie conditions of abso- 
lute repose wliieli are so essential to the foiination of cryetals 
troni ordinur^ ealina gcrlutions. 

One of tlie most interestiiiig points in theBe experiments 
is couiiecteiJ with the iiifiut'TitG of the coinpoaition of the 
blastema upon the development of leucocytes. It was found 
that these bodies were never developed in a blastenia in 
which the fibrin had been eoagnkted, Experimcntitig with 
iTfy ]i«|uid$, tht on]y difference in their constitution bein^ 
tLiiit ill one the fibrin had been coagulated by repeatedly 
plunging the glass tubo in which it was contained into cool 
water, wJiile the other ws& kept at the ordinary temperature, 
a little bii'jirbonate of eoda being iiddtjJ to prevent coagula- 
tion, it was found thiit leucocytes were developed as usual in 
the fluid which contained its fibrin, and that none appeared 
in the other. On placing the liqnicl, with its coagubini, eu- 
clo6ud in a sac under the skin, it waa found that, after a tiiuej 
the fibrin w«6 redissolved, but no leucocytes made their ap- 
pearance. 

The theory which has for its motto, (wnnw ceUuIa e cellula, 
receives no support from these experiments. Onimus added 
to fluids which had been deprive(l of tbeirfilirin, epithelial 
cells and pus-corpuecles, but, even alter thirty-six hours, bo , 
never Ibiind any additiunal development of eorpufii-ular ele- 
ments. Leucocytes added to finids in whieh the fibrin was 
Unchanged did not seem to exert any influence ujion the d&- 
Telopnient of new corpuecles. 

E terneniarr/ Corjtrrscf &t.—Litt\G grannies arc found in the 
blood, efipociftlly during digestion, whii-h, as they were sup- 
poBcd to take part in the formation of the white corpii£clea, 
liftve been callcil elementary grannies or corpuscles. They 
probably are little fatty particles of the chyle which come 
from the thoracic duet, and are not iioeitively known to 
have any connection with the formation of the other cor- 
posc'ular elements of the blood. 



128 IHE BLOOD. 

Coniposiiion of the Red Corpuscles. 

The red eorpusclcB of the blood contain an organic nitro- 
genized principle, called globuline, combined with inorganic 
principles and a coloring matter. The composition of the 
leucocytes has not been accurately determined. The inor- 
ganic matters contained in the red corpuscles are in a con- 
dition of intimate nnion with the other constituents, and 
can only be separated by incineration. ' It may be Btated, 
in general terms, that most, if not all, of the various inor- 
ganic constituents of the plasma exist also in the corpuscles, 
which latter are particularly rich in the salts of potassa. 
Iron exists in tlie coloring matter of the corpuscles. In 
addition, the corpuscles contain cholestorine, lecethine, a 
certain amount of fatty matter, and probably some of the 
organic saline principles of the blood. 

Glohdine. — Rollett has succeeded, by alternately freezing 
and thawing blood several times in succession in a platinum 
vessel, in separating the coloring matter from the red cor- 
puscles.' "When the blood thus treated is warmed and lique- 
fied, the fluid is no longer opaque, but is dark and transpar- 
ent. Microscopical examination then reveals the corpuscles, 
entirely decolorized and floating in a red, scmitransparent 
serum. Denis' extracted the organic principle of the cor- 
puscles by adding to defibrinated blood about one-half its 
volume of a solution of chloride of sodium, one part in ten 
of water. Allowing this to stand for from ten to fifteen 
hours, there appears a viscid mass, which is very carefully 
washed with water, until all the coloring matter and the salt 
added has been removed. The whitish, translucid mass 
which remains is called globuline. Denis has also extracted 

' KoLLETT, in Stricker, Manual of Human and ComparaiiM Hiatologi/, The 
New !<yileiiliaiii Socictj, London, 1870, vol. L, p. 308. 

' Dknih, Mintoirt tiir U lOHff, Paris, 18Q9, p. 19. The manipuUtions for the 
extraction of globuline are minutely described m the above memoir, which iuit& 
dutes con&iderabljr the obaerrationa of Bollett. 



H-fiUAQLOBIXE. 120 

a small quantity of fibrin from the corpuscles. Glolmlinc 
is readily extracted from the blood of birds, but is obtained 
with difficulty from the blood of the human Bubject. 

ffcana^obins. — This is the coloring matter of tho red 
corpuscles. It has been called by diiferent ■writers, linema- 
globnline or htematocrystalline, but the crystals called htema- 
tine and hipmatoBine are derivatives of hecmaglobine, and 
are not true proximate principles. Ha?magIobinc may be 
extracted from the red corpuBcles by adding to them, -n'lien 
congealed, ether, drop by drop. A jelly-like mass is then 
formed, which is passed rapidly through a cloth, erystuls 
soon appearing in tlie liquid, which may bo separated by 
filtntion.' 

. The crystals of hiemaglobiiie extracted from human blood 
ire in the form of four-sided prisms, elongated rhomboids, or 
lectangalar tablets, of a purplish-red color. They are com- 
posed of carbon, hydrogen, oxygen, nitrogen, suljihur, and 
Ismail quantity of iron. They are soluble in ^vatcr and in 
very dilute alkaline solutions, and the liseniaglobinc is pre- 
dpitated from these solutions by ferrocyanide of potassium, 
nitnte of mercury, chlorine, or acetic acid. Tlic proportion 
rf tluB coloring matter to the entire mass of blood is about 
127 parts per 1,000. It constitiitcs about U or -^^ of the 
4ied corpuscles. A solution of hojuiaglobine in 1,000 parts, 
tttmined with the spectroscope, gives two dark bands be- 
t*«ca the letters D and E in Fraucnhofor's scale.' 
I Treated with oxygen or prepared in fluids in contact with 

* *I» flir, there occurs a union of oxygen with the coloring 

"wtter, which has been called oxyha'niaglobine. There can 
I w ao doubt that the oxygen enters into an intimate, though 

'■fter nustable, combination with h«?maglobine; and this is 
■n important point to be considered in connection with the 
*Diorption of oxygen by the blood in respiration, A solu- 

Quno, C^imit a^iguie d la phytioltiffie, Pari^ Wii, tome i., 404. 
' Cuno, cp. eii., tome i, p. 460. 



130 



tiou uf osyliK-maglobine presents a different epectrum from 
a solntion of pure lia^niaglubme. If we exnmine a solutioa 
of oxylimjiuagloliine with the spectroscope, and then discharge 
the osygea by prolonged ebullition in a vacuiiin, tbe charBO 
teristic bands of pure IisemaglobinB make thcii* nppearance. 
Tbe uiiion of oxygen with bfEmai,']obi]ic 13 unstable, nnd ibe 
oxygen can be removed by a current of hydrogen, nitroiu 
oxide, or carbonic acid. A current of carbonic oxide die- 
plnccs tlie oxygen, and tbe carbouie oxide foiiiis » very sta- 
ble combination witb tbe coloring niiitter It ie well known 
that carbonic oxtde is a very ])oisont>ua gae, and becomes 
fixed in the corpuscles ao that they are rendered incapiible of 
absorbing oxygen. 

According to recent observations, o:xygen combined witb 
bsemaglobine exists in tbe condition of o^one. A fiolution 
of oxyhtemaglobiue is readily decomposed by a current of 
Bulphuretted hydrogen, forming, like ozone, water and a pre- 
cipitate of Bulpbur.' 

Hieniatine may be produced by decomposition of ba?nia- 
globine, by a proceB& which it is not necessary to describe, 
aa tbe lueiniitine is not a proximate princi|.de. Ha'niatoi- 
dinc is also a product of decom position of ba^maglobine, but 
does not contain iron. ITjpmatoidine is more interesting, 
however^ frym the fatt that It is frccjuontly ft>iind in old elota 
that have been long extravaested In tbe tissues. Robin 
found a notable quantity of crystals of bffimatoidine in a 
cyst of the liver.* 

' Gactiir, Chimit af^Jiynkii la ph;jti^f>ffir, Vens, 1874, tome L, p. i'Jt, 
• RoBEit, Jlrpftu sur la Aumcvrt, Tana, ISTl, p. OH. 



CHAPTER II. 

ooMPoemos of tue blood-plasma. 

AnalTsis of the blood for fibrin, corpuBcles, and albumen — Composition of tho 
blood-plasma— Flaemine, fibrin, metalbumcn, and seriae — Peptouea — Col> 
oring matter. 

Abbumino, as we certainly nmst, that the hlood furnishes 
material for the nourishment of all the tissues and organs, we 
should expect to find entering into its composition all the 
proximate principles existing in the hody which undergo no 
change in nutrition, like the inorganic principles, and organic 
matters capable of being converted into the organic elements 
of every tissue. Farthermore, as the products of waste are 
all taken up by the blood before their final elimination, these 
also should enter into its composition. With these facts in 
our minds, it is unnecessary to insist upon the importance 
of accurate proximate analyses of the circulating fluid, to 
which so much attention has been given within the last 
few years. 

It is not many years that our knowledge of the laws of 
nntrition and disassimilatiou has enabled iis to appreciate 
the fiill importance of the blood ; but it has been so palpable 
that this fluid is necessary to life, that the older pliysiologists 
made numerous attempts to obtain an idea of its composition. 
However, we have only to go back to the beginning of tbe 
present century, to find the first analyses of the blood which 



133 



THE BLiVifi'. 



■were attciudcd with anv degrt-e of success. In 1808, Bcrze- 
liuB anulyzed tlie serum of the LumaiL blood, mdicating cer- 
tain proportioiiB of albumen, lactate of eoda, muriate of emla, 
etc He waa followed bj Marcet, in ISll, by Trliom his ob- 
Bervations were confirmed. In 182:^, Pi-^vost and Biiiuas 
published their ehiboi-ate refiefiric:ljes into the composition of 
the bluod, M-Lich gfive ft strong tmimlse to investigations in 
tUU direction, aud were won followed hy the analvsea of 
Andi'fil and Gavurret, Leiiinaini, Simon, Beequt-'n.-! and Eo- 
dier, Duuia, and a host of otberB, whose labors have made 
MB comprehend sonic of the nioftt important Jaws which regu- 
late the general proccflSCB of nutrition. 

NotwithBtanding the imnieni<e amount of labor beatowed 
by the most eminent chemists of the d:iy upon the quantita- 
tive analysis of the blood, aud the great physiological interest 
attaching to every advaiice in om* knowledge m this direc- 
tion, the chemical clifliiculties involved are so great, that there 
are now no analyses which give the e-xact quautitioB, even 
of ite Inorganic cunstitueuts. This ie owing totlie great dif- 
ficuliy iu the a7ialyeis of any fluid in which inorganic and 
organic principles are so cloBely iintted ; for there is no more 
delicate problem in analytical fhemietry tliau the deterinina- 
tion of the presence and qiiantities of iuurganiL- eubetances 
united with organic matter. Of the animal fluids which are 
easily obtflinod, the blood, from the large proportion uf dif- 
ferent organic principles whli.'b eutcr into its composition, 
prescntB the greatest difficultiea to the analytical fhemist. 
Auotlicr difficulty is the ueccBsity of a proximate, aud not 
an ultimate analysis. It is not sufficient to give the amount 
of certain fhemical elements which the blood contains; we 
must ascertain the amount of these elements in the state 
of union with each other to form proximate principles. 

Most of the constttneate of the blood are found both in the 
corpUoL-les and plasma. It is difficult to determine all of the 
difl'crent constituents of these two pnrtft uf the blood. It has 
been shown, however, by Schmidt, of Borpat, that the i>hoe- 



QtTAimTATIiaBJtSAXTSTS. 



133 



pliurizcil fate are raoro abundiint in tlio coi'iniBde&, wliJle the 
fittty ac-ids are more abimiliiiit in the plasma. The suWb with 
a potash-hnse have been foiiiitl by the ejiiiio oheerver to exiat 
almost entirely in the corpuscles, and the Boda-snlte are four 
times more abundant in the plasma than in the corpiisclL-s.' 
Ill addition to the nutritive pniuiples, we lulvCj cuti^riu^' 
into the compoeitioa of the blood, urea, cliolestmne^ urate 
of BOiln, iTeatiae, ereatiiiiiie, siiJ other siibfetiinctis, the char- 
acters of which ai'o not yet t'tdly determiued, belonging to 
tlie class of estTcmentitions pnnciples. Their eooBidcration 
comes more nppropriately under tlio head of e-xcii'etion, and 
they will be fully taken up m the uhaptere devoted to that 
Bul^'eet. 

Although ft knowledge of the exact proportions of the 
various elumenta of the blodd is not neL'essai*y in order to 
appreciate the relations of thit fluid to tlic tisi^ues, the great 
intereet whJeli la attached to this line of iuveetigiitiouj and 
tho important advautageu which we may look fur in the 
future ti-oin extended inquiry in this direction, lead us to 
discui^s at some len;^th tho methods which have been em- 
ployed by physiological cheinisLs in fpiantitatlve analvBcs, 
with some of the rcaultid w!iich have already been obtjiiued. 

Qnantitative Anahjsh t^f the Blood. 

Tho methods which have been, and are now, commonly 
employed for qiiaatitativo aualysis of the blood vajy very 
little from the procB63 recommended by Prevuat and Dumas, 
in IS^y. They are based upon the euppoeitiou that the 
organic crouetituents, which were then called fibrin and albu- 
men, are solid substances in suhition in tho watei-j- elements, 
and that all the water of the blood is to he attributed to the 
serum. As we have ahown, in treating of organic sul> 
stances, that this view of their condition in the iluids ia 
erroneous, and that the desiccated msterials obtained ti'om 

> CWn^ by UiLHS-Exnuwa, Lt^ont tur la phi/rioiw/u, Paris, I^ET, tome Lj 
p. Slid. 



131 THE BLOOD. 

the blooJ do not represent the real quantities of its organic 
elements, a new method of annlysis, based on the view that 
these principles are naturally fluid, seems necessary. The 
same process has been employed for the estimation of the 
proportion of corpuscles ; and here the error is too manifest 
to require discussiop. It is evident that the blood-corpuscles 
are semisolid bodies ■which become altered by desiccation ; 
and an estimate which does not give their weight in their 
natural, moist condition gives us no idea of their real pro- 
]M>rtion. So apparent has this been to physiological chem- 
ists, that attempts have been made by Denis, Schmidt, Vie- 
rordt, Figuier, and others, to estimate the moist corpuscles ; 
but, in attempting to attain extreme accuracy, these observ- 
ers liave ahnost entirely failed, and their ideas of the real 
proportion of the corpuscles are merely conjectural. These 
remarks apply only to researches into the organic constitu- 
ents of the blood. The analyses with reference to the in- 
orgauie elements, though they have not yet shown us the 
exact proportion of each one of them, are of course accurate 
as far as they go. 

The various processes for analysis of the blood now em- 
ployed by chemists do not differ very much. As one of the 
best, we may take that recommended by Becquerel and Eo- 
dier. Their process, which we shall give in its essential par- 
ticulars, has an advantage over most others in simplicity. 

Two specimens of blood are taken and carefully weighed. 
One of them is defibrinated, the fibrin collected, dried, and 
weighed, which gives the proportion of fibrin, Tlie other is 
set aside to coagulate. A known weight of the defibrinated 
blood is then evaporated to dryness, and the proportion of 
dry residue carefully estimated. The residue is then calci- 
nated, to give the proportions of inorganic constituents which 
remain after the organic matters have become volatilized. 
After the blood set aside to coagulate has separated into clot, 
and scrum, a definite quantity of the serum is evaporated to 
dr\-ness and the residue estimated. As the dry residue of 



QrAHnTAHTB ANALTBI8. 



135 



tlie defilirinnteJ btbod coiitaine the 6o]id matters of the Benim 
plus the di'iecl eorjmselcs, the proportion per thousaud jiarta 
of rho solid niHttLTs of the defihriii-itcd hlfitid k'tjs ibe pro- 
portion per thousand parts of the Bolid matters of the serum, 
woidd ^ve the proportiun of corptiBck'S.' 

We have Ihus obtained the proportions of water, of inor- 
ganic matter, of corpuBcIes, and of fibrin. The next step ie 
to eetimate the albunieu, fiittj, and cstractiye matter. For 
this purpose, wc desiccate a known quantity of serum, c-fire- 
fully pulverize the dry rceidue, aiid treat it repeatedly with 
boiling -watGir until it has washed out all Bolnble matters. 
These are nudetermined extractive matter&, and free salts 
in solution in the semm. The residue, thus treated with 
boiling water, is dufiiccated and treated several tiiues with 
boilinj; alcoliol, which dissuEves all the fatty substatices. The 
insoluble residue is then dried and wcig-hed, and re]>rcBeDts 

' Tliit ubore \a condensed fTuin Qecutterel nnd Rodtea, " Tniiti de nkimu 
patKoloffi'/'ir aj^iquii! d la midte\itt prali^/f," Paria, 18M, p. 21, rf »i^, Aa 
Ihe repiuU of ausil^i^t^s of the b](H«3 of twenty. Urn healthy peraoiia, these antbore 
f;lTu ihe rolluwin^ tiible [puge Sti). Th« li:<t of isorgdiiic salts Is tuktb fiom 

i>«*tjnj(ti»ni«id „ .,.. .,,,. ma 

VTkUi-. TSl-GM 

GliHl.uJei., .., , , „., laS-OIW 

AlbUHIPD TIMMMI 

Pllniii .....4... SJWO 

BwoBdb,,,, , 0-02B 

CniolesUriDV. , D-tU 

OleatB, inarg»nite. ud ■tninte Af Md*. ., l-iOU 

ChMdc* of Bodluia. putiudluiu, uid mngiicBlQia. 8-SOO 

CtrlHiuia of iHb 



Frw i»tii, 

Sulphilu of (odi. 

fTm-phW* flf iMtIt 

Cv^lutf of giobw.-.. 
Bulptite " .... 

PlHlSJlfllllO " ,,., 

rhiHpIuit* of UmB. I 

Plin«[illltli dl UUJBlilIt,,, ( '■"" 

Jmo , ...,,..., 

ITadvlcnnliud ■ztnot)** mtUtn 



(Cutxnulo of iDdi DiMl ibonduit).. 



!-KK) 



OtoVt 



l,W>ilOW 



136 THE BLOOD. 

pure albumen, wbich, it will be remembered, is not dissolved 
by boiling water or alcobol. The loss after treating with 
boiling alcohol gives the quantity of fatty matters. The 
proportions of inorganic matters are obtained by analysis of 
the residue after incineration. It is unnecessary to describe 
the complicated and difScult manipulations involved in this 
process. 

The above process is perhaps as simple and reliable iia 
any ; but of course eauh chemist has some slight modifica- 
tions. By some, the corpuscles are estimated by drying the 
clot after coagulation and deducting the weight of the fibrin. 
Some recommend to expose the fibrin after desiccation to in- 
cineration, and deduct the weight of the residue of inorganic 
matter. All of the processes, however, are materially the 
same, and differ but little from that employed by Prevost 
and Bumas. As before remarked, the results, as regards the 
fatty and inorganic constituents of the blood, are as accurate 
as possible with our present means of investigation ; and tbo 
comparative results, in analyses of the blood for fibrin, albu- 
men, and corpuscles, in health and disease, which have been 
developed by the labors of Andral and Gavarret, Becquerel 
and Rodicr, and a number of others, are of permanent value. 
But a glance at the process, and the quantities given for the 
fibrin, albumen, and corpuscles, indicate that the whole is 
inconsistent with our ideas of the conditions under which 
these substances exist in the body. Microscopical examina- 
tion shows that nearly one-half the mass of the blood con- 
sists of corpuscles, while analysis gives only one hundred and 
thirty-five parts per thousand. The fibrin of the blood is 
sufficient to entangle, as it coagulates, all the corpuscles, 
and with them to form the clot ; yet we are told that its 
proportion is two and one fifth parts per thousand. We 
boil the scrum, the albumen changes from a fiuid to a semi- 
solid condition, and the whole mass is solidified ; yet the 
estimate of its proportion is seventy parts per thousand. 
The fact is, that these estimates g^ve us only the dry residue 



QrAKTITATIVE ASALYSI3. 137 

of the organic principles ; and, to form an idea of their actual 
proportion, wo should estimate them, if possible, with their 
water of composition, and united with the inorganic salts, 
vhich cannot be separated from them without incineration 
■ad consequent destruction. 

In the analyses given in the older works on physiology, 
the blood, having been divided into plasma and corpuscles, 
was BuppoBcd to contain, in the plasma, the two organic 
principles, albumen and fibrin. Recent investigations, how- 
ever, have shown that the organic constituents of the plasma 
are more complex ; and that the matters which were called 
albumen and fibrin are compounds of other organic prin- 
ciples. Still, we frequently speak of albumen, a principle 
coagulated by heat, the strong mineral acids, and alcohol, 
and of fibrin, a spontaneously-coagiilablo principle, as exist- 
ing in the plasma ; and it is important to know how these 
matters are separated from the blood and recognized. To 
meet this want, we devised the following mode of analysis 
of the blood, which i^ easy of application, siiflicientl}' accu- 
rate for all practical pui-poses, and gives the proportion of 
fibrin, corpuscles, and albumen, as nearly as possible in their 
natural condition ; that is, containing water, wliieli is noces- 
■ary to the manifestation of their peculiar and characteristic 
properties.' 

The blood to be analyzed is taken from the arm, and re- 
ceived into two carefully-weighed vessels. The quantity in 
each TCBsel may be from two to four ounces. One of the 
■pecimens is immediately whipped with a small bundle of 
broom-corn, previously moistened and weighed, to collect the 
fibrin $ and, after the fibrin is completely coagulated, the 
whole is carefully weighed, deducting the weights of the 
Teasel and broom-corn, which gives the weight of the specimen 
of blood used. The other specimen is set aside to coagulate. 

' Fun, Jr., 7S« Organic Xitrtigeniifl I'finrijilit if ihc Soilff, vH/i a AVw 
mtkod /or their Ettimaiiou in Uit BluoJ. — Aimruan Jourmd uf the MulhtU 
SekiMm, FhilKdelpfaiE, October, 1BC3. 



138 



THE BLOOD. 



The first epedmen is used in tbe eetimation of the fibiin 
and corpusvles; the second i& set aside to congulfite, and is 
ueed to estimate the albumen. It is important to cover the 
vessels as soon as the blood is drawn, for blood exjiOBed to 
the air loses weight rapidly by evH[joratiou. 

We now pass the first Bpecimen of blood throtigh a fine 
sieve, to colk-et any fibrin that may not have become attached 
to the wisp, strip the fibrin froin tbe wisp, fltid wash it under 
a stream of water. This may be done very rapidly if we 
catise tbe water to flow tbrotigb a small strainer, by which it 
is brokun up into a nnnibcr of iittle streams, and knead the 
fibrlu wilk the fingers^ doing this over n siovEj eo iis to catch 
any pnrtieles that may become detaclied. In this ^rt, tho 
fibrin may he freed from eorpuedes in five or ten minutes. 
Tbe fibrin is then freed IVoui most of the adherent nioiature 
by bibulous paper, and weighed as soon as possible. By the 
foHowiug formula, we estimate tbe proportion per 1,000 
parts of blood : 

Weight of blood used : Weight of fibrin : : 1,000 : Fi- 
brin per l,(fOO. 

The nest step is to estunate tho cor|m6c!es. Tor tlu9 
purpose, a portion of the defibrinated blood, which is care- 
fully weighed, is mixed with twice its volume of u saturated 
solution of sulphate of soda, and thrown upon a filter which 
has been carefully weighed and moislened with distilled 
water, and also, just before rt-H*eiving the mixture of blood 
and sulphate of eoda, with tbe saline solutiun. The fluid 
whifh passes through shmdd bo ftliont the color of the Bernm ; 
if a few corpuscles pass »t fir&t, the li'iiiid should be poured 
back until it becomes dear. The funnel is then covered, 
and the flnid allowed to separate, tb« blood-eorpuKdcs being 
retiiinod on the filter. The filter and funnel are then plunged 
several times into a vestiel of boiling water, by which all the 
sulphate of eoda which remains is washed out, and the cor- 
puscles arc coagulated without changing in weight. The 



QUAJNTITATIVE ANALYSIS. 139 

fonncl should be again covered and tlie water allowed to 
drip from the filter, after which it is weighed, deducting 
the weight of the moist filter previously obtained, which 
gives the weight of the corj>u8ele8. We obtain the propor- 
tion of corpuscles to 1,000 parts of blood by the following 
formula : 

Defibrinated blood used : Corpuscles : : Defibrinated 
blood per 1,000 : Corpuscles per 1,000. 

The nest step is to estimate the quantity of albumen in 
the seraiD, and thence its proportion in the blood. For tbis 
pnrpoae, we first ascertain the quantity of serum in 1,000 
parts of blood, which is done by subtracting tbe sum of the 
fibrin and corpuscles per 1,000 from 1,000. Having done this, 
and waited ten or twelve hours for specimen Jfo. 2 to sepa- 
rate completely into clot and sci-am, we take a small quan- 
tity of the serum, about half an ounce, weigh it carefully, 
and add suddenly twice its volume of absolute alcohol. The 
albumen will be coagulated into a grumous mass, and the 
whole is thrown upon a filter, wliidi has been previously 
jnoiBtened with alcohol and weighed. The funnel is imme- 
diately covered, and the fluid separates from the albumen 
▼ery rapidly. Wo aseertain that no fluid albumen passes 
through the filter, by testing tbe filtrate with nitric acid. 
After the filter has ceased to drip, it is weighed, and the 
weight of the albumen ascertained Ity deducting the weight 
of the filter. The proportion of albumen to 1,000 parts 
lof blood is obtained by the following formula : 

Scrum used : Albumen : : Serum per 1,000 : Albumen 
per 1,000. 

The above process has at least the advantage of sim- 
plicity and fiicility of application. As regards acciiracy, 
haying repeatedly made analyses of diflerent [lortions of the 
aame fluid with almost identical rcf:nlt»:, it has seemed suf- 
ficiently ezast for all practical pur}}u8es. As an example. 



140 THE BLOOD. 

wc may mention an analysis of two equal portions of defi- 
briiiated blood (34*20 grammes) for corpuscles. One specimen 
gave 16'40, and the other, 16'43 grammes. Tliis part of the 
process would seem more open to the objection of inaccuracy 
than any, yet tlie difference of the result in the two aniilyses 
is so slight that it may be disregarded. Repeated examina- 
tions of difierent specimens of the same scrum for albumen 
were followed by identical results. While the ext-codiug 
accuracy which is desired by chemists, and is necessary in 
many analyses, is not attainable in such examinations as 
these, it is not even desirable; for, as physiologists, we must 
see that even an approximation of the proportions of the 
organic matters, as they really exist, is better than the most 
accurate estimate of their dry residue. In taking the weights, 
the only point is to do it rapidly and avoid loss by evapo- 
ration. If this be borne in mind, and care be taken in dif- 
ferent examinations to weigh the principles at the satnc stage 
of the operation, the simijlicity of the process should make 
it valuable in comparative analyses of the blood in different 
conditions of the system. 

In estimating the proport;ion of fibrin, the ordinary 
method is followed, with the exception that the weight of 
the moist fibrin is taken instead of the dry residue. 

In estimating the corpuscles, after a number of trials, the 
process recommended byFiguierwas adopted, with a similar 
modification. Figuier dried the corpuscles after separating 
them from the serum by filtration, taking advantage of the 
property of sulphate of soda, which retains them on the filter. 
He employed this method to separate the corpuscles com- 
pletely and investigate their cliemieal constitution.' 

In estimating the albumen, the object was, as in the case 
of the other principles, to obtain it as nearly as possible in 
its natural condition, simply changing its form from fluid to 
semisolid, without adding any thing which would decompose 

' KiouiKR, Svr line yniihodt ttovvtllf pwir VanaliiK dtt tang. — Aiinalet Ji 
chhnif it 'Ir phgtique, P&riB, 1844, S"* B^rii<, tome xi., p. S06. 



QUANTITATIVE ASALrSIS. 



Ul 



it or unite with it. For this purpose, absolute alcciliol seeiifed 
better iLiin hc-at, nitric* aLid, the galvanic^ current, or any 
otiitT agents by vrhkh albumea la coagulated. 

If llie difterent organic prineiples be incinerated, tlie ash 
wi]] prcsonl the tharact eristic reactions of the fhlurides, buI- 
phules, phosphates, etc., inorganic principles, which cannot 
be se]>arntcd ("rom the organic constitneuts of the body with- 
out destruction of the latter. 

Tlio blood of a healthy male, ffit, S7 years, weight 170 
pounds, who had never eiiffered from disease,, tidien from the 
ann at 1 f . m., the last meal having been taken at 8 A. m., 
furnished the following proportions of organic coustituente : 



■ 



f^'m 8'S2 parta per 1,000. 

CWpwri** *os-5fl " " 

AOumen 8*i0'82 " " 



Physiological cheniiEte are not now content with the 
shnple terms fibrin and albumen ; and the more modem 
analyses of the blood give other organic principles, which 
have been separated by new methods. As tliese have been 
<jTilte generally accepted by modem Ht-iterB, it becomes neces- 
sary to descrihe them in detail, and we shall adopt the new 
nomenclature, as far a& the diflerent organic principles have 
been estnbliEhed by definite ohaervations. An argument in 
favor of (Ills snlxlivieion of the matters formerly recoit^kcd 
as fibrin" and albumen is the fact, which has long been ap- 
parent, that the organic constittientB of the blood, particu- 
larly albumen, are known to possess certain peculiar jjroper- 
ties which dietingiiSeh them from tht'se priticiplcs as they 
are found elsewhere. Tlio following table, which we have 
carefully compiled from recent autlioritiep, partlcxdarly 
Hobin,' gives approsimativcly the tpiantitiee of the diflerent 
constituents of the blood-plasma. These may he divided 
intu the following classes ; 1. Inorganic ]irinciples : 2. Or- 
ganic aaUne prinei]jlc9 : 3. Organic non-nitrogenized pria- 

■ RoBni, irf-fOiu «ur la humturi, PuU, 1S?4, p. &9. 

10 




THE Bl,OOI>. 



IBOOpcirU 
per 1,000, 



ciples : 4. Escrementitions matters : 5. Organic nitnigeuizod 
pi'inci|)les. 

Composition of the mood-Plasma. 

[Spceific gMTity 1088.) 

' Water, 7 1* parts per l.WKiiii ihe [unle; 7^1 pnrteper KOOOiu tb(irt.'mBlc 
ChloriJc of joiliiim, 3 to 4 pKn." pRT l,iiiiO. 
" " potassiiirn, O'Sftfl pnrta pPr l,(KK>. 

" " nuitiiniiium, proponian not itetennined. 
Sulphate orpoiasso, U'^US parts per l.OoO. 

'' " Eotin, pToporti-da ooi detcrniined. 
CuboaALG of potassii. " " " 

"' " iio'liL (driili Iiiuiirbonate ol'^O'Ia)', I'&DO pnTti por 1,000, 

" " liiuu, proportiyQ nut dclerroined. 
" " luagDE^ia, " " " 

I^uBpliHteoriiuiKoftbe bonea, nnd neutral phoapb&Ce, 
" '■ mttpii-aia, 

" ■" poUiiisa, 

" " iron (pi-oliable), 
ItasiL' phoapliuiL-)! and uoutru] pIioBphntc of «0(I«, 
^ .SilEL-u., CDppiiT, Bead, uid ni&g-nL'nLn, tTKcca occaflioiiBUy. 
Luetabe dTHKla., proporlidD not dutrrtnlntrl. 

" "' Ume (probable), proportioa uut determined. 
Pneiimalaorsoda, " '" " 

Jlur^arate uF soda, 

Kiearite " " 

Vakral« " " 

Ruirratc •* " 

liMne, 

Miir^arine, 

Siimrine. 

Lt-Li^tliini?, cotttiiluitug niti-og'TO and call>ed pboaphorized r&tt; maUer, 0-400 

]iiLrts pel- 1,<HX>, 
Gluecioe, n-002 purM per I.OOO-. 
(ilycoi^iLic mailer, praportLon not det^niaiui.'di 

loOSiti.' (mUHclcS), " " " 

Cnrbonate kcid in solutinn. 

I'riM, u-llY parls per 1,W0, in arierid tilood ; 0-08fl fa the blood of tb« 

renal rein. 
Urate of sada^ proportion not ilptemiined. 

" pntHssu (probiibli!), proporlign nol ^Qtertuiaed. 

" ilme, " " " " 

" mngrvMia, " " " " 

" «njBioniB, " " " " 

SnilnratM of soda, rtft, " '• " 

InoMtee, " " ■' 

Oiiliiiw, « " '■ 

CK*Ufte, » 11 u 

Cnjutinino, ~ ' h k h 

LmiciuG, M u i> 

HTpoum thine, " " " 

Cholesterme, 0-44S tQ OTSU pMW pflr 1,000, la the entJpe Wood. 



■ l-4ia pkrti pi<r 1,000. 



QUANTITATITE ANALY8H, 



143 



Serine, 6^ parts (dri^) per ],(XtO. 

(M'lUi (itittii, 8-820 parts per 1,'W), of thy irolire bloo4, 
MeiAitiuirii'D &iid seTint cDtis^iFtute ttie lUttumeD of Hia older uioJ- 
ys<.-s. Albuinvii, iiboiLl TU jinrtH (drii<(lj Mud 330 parts (moiBt)^ 
pi'r-l,''*ii, of ilie pniii'« bl«<Hj.) 

feistone?, 4 (laris (lUienlj «m! 3H fjsru freoist) per 1,000. 

Cciloring maUL'Jil uf llii; |>1ii£Iqu, [impurtiuLaliil I'burfl.cltE'SiiOtdetCrlDiiied. 



"We shall take the almve table an a guide for our etudy of 
the individual eonstiEucnts of tlio bSood-plasraa. As rc^rda 
gaseSj in ndditiuii to carboiiie acid, wliit'li we have classed 
with the exercmcutitions matters, the Wood ccintaina oxygen, 
nitrogen, and liydrogen. The nitrogen and hjdrojjen are 
ti<.it ijiiportant, and the relations of oxygen will be fuily con- 
sidered under the head of respiration. Most of the coloring 
matter of the blood exists in the red corpuecles, wbieh con- 
tain a peenlinr principle "wbit-h we have already fully con- 
BJdcred in ennneetiun with the chemical eonfititntion of these 
bodies. 

In studying the coraposition of tlie blood, as ircll as the 
composition of food, the tissues, seereted fluids, etc, it ia 
convenient to divide Its constituents into chisses, and this 
we have done in the simplest manner poseible. 

It is evident, the blood receiving all the products of dis- 
aaaimiifltiuu, as well aa the nutritive principles reeuUiiig from 
digBstion, that there should he a division of ita constituents 
iDtu nutritive and excrenientitious. We have classed certain 
principles together as excrenientitious. These are the vari- 
ous products of disassimilation of the oTganisin, which are 
taten up by the blood or conveyed to the blood-vessels by 
the lymiihatics, exist in the blood in small quantity, And are 
eonelantly being separated from the blood by the difl"t;rent 
excreting orgsins. Thcii' couetant removal from the blood is 
the explflnation of the excessively ininute proportion in which 
they exist lu this llnid. Their relations to the organism will 
be fully considered under the head of excretion. 

Excluding, then, for the jiresent, all consideration of the 



144 



THE BUX)D. 



producte of disaseimilatinn, vre have to study the various con- 
stituents of tfie blyod tbat are more or lees directlj concerned 
m DUtrition. 



1. Inorganic Prineip!4;8.—A& examples of this elaee, we 
may cite water, cldoride of &odiimi, the carbonateBj siilpliates, 
pliosphates, and otlier inorganic salts. 

The functioiiB of water in the Llood are eufficicutly evi- 
dent. It acta as a solvent for the inorganic salts, the organic 
fiftlte, and the c^crementitioui matters. In conjnuction with 
the nitrogeuized priiiciples, it cotistiEutes a medium in wLifli 
the corpuscles are suspended without solution. 

The various salts enumerated in the ta!)le of composition 
of the blood exist in folutiou in the water, and arc more or 
lees intimately combined with the coagulablc organic prin- 
eiples. Of these, the chloride of sodium is the most abnn- 
dant. It undoubtedly has an important tiinetion in giving 
density to the plasma and in regulating the processes of eu- 
dosmosis and exosniosis. In connection with the organic 
ealts and the cr;rstallizable excremeHtitloUB matters, it nmy 
be stated, in general ternm, that tbo blood contains tj'om 
fourteen to si.xteen parts per thousand of matters in actual 
Bolution, of which from six to eight parts consist of luor- 
ganic salts. The presence of these principles in Sf.iUuiun, 
with the organic coagulablc principles, prevents the solution 
of the corpnsculai' elements of the blood. The presence of 
llie chlorides nnd the alkalldu sulphates assists in di&solving 
the BuSpbates, carbonates, and the calcareous phosphates. 
The carbonalCB and phosphates are in part decomposed in 
the tystcm and ftiriiifih bases for certain of the orgnuic salte^ 
such as the lactates, urates, etc. 

2. Organic Sal'me Principles. — These principles are for 
the most part formed in the organism, and they exist in the 
blood in very small quantity. The lactates are probably 
produced by dcL-omposition of a portion of the bicnvbonfltea 
and the union of the bases 7ith lactic acid, the lactic add 



QrANTTTATrVE AKAI.V9I9. 



145 



resulting from a change of a portion of the eaceharme matter 
in the lilootl. The piieumate of sorhi l^ the result of tlie 
union of piienraii; acid, an acid priiicsple Ibuml in the lungs, 
with the base. The physiological relations of these priu- 
ciplcs are little understood. The ealtu formed by the union 
of fattj acids ivith bases are pi'obablj" produced by decom- 
pusitton of the fatty priuciplee, a great part of whk'h is de- 
rived from the food. 

3. Oi'fjaiiie Non-nit rogenizeil Principles. — These usually 
exist in tha blood in small quantity and are derived mainly 
from the fond. Lecethine, though it cuiitaiiis nitrogen, is 
introduced into this class bccmise it presents many of the 
properties of the fata. It exists in rhe blood, bile, ner- 
vous substauce, and the yolk of egg. This principle is sup- 
posed by Robin to be almost identical with pi'otagon.' Its 
chemiciil properties and physiological relations are not 
well understood. The sacchaiino principleB and the gly- 
cogL-niu matter are derived in part from the food and in 
part from the liver, where sugar and glycogenic matter are 
found. 

4. KccreimntU'ioiiB Matters. — A full consideration of 
these principleB, which aru all formed by tbo process of dis- 
assimilatiun of the tisduos and are taken iip by the blood to 
be eliminated by the pmper organa, belongs to excretion. 
The rclationfl of cjirbonie add to the system will be fully 
considered In connection with respiration. 

5. Onjanlc NUrugenh&l Prln^cipf^s.^Ot tba different 
classes of proximate prineiplea existing in tho l>luc)d, it is at 
Oflce apparent that the organic nitrogeni^ed principles are 
more complex in their constitution, properties, and fiinctiona 
than the other clasBc-s. These prineiples, as they exist in the 
blood, possess peculiar and characteristic properties, which 
it will be necessary to study in detnil. 

PhwriiTie, Pibriiif Metalbumen, Serine.- — The name plas- 

' RoBiy, Lepmt tur U* httmcars, pB.rts, 1874, p. 81. 



lio 



TOB BLOOD. 



mine was given by Denie' to a peculiar principle wLieli he 
extracted from the blood by tlie lallowmg process : The 
blood (Irftwn directly from an artery or vtin is received into 
& vesEg] containing one seventh part of its volnme of A con- 
cetitrated solution of eulpliate of soda, M'hidi prevents coagu- 
lation. In a short time, tliG coq:)ueo]pe gravitate to the bottom 
of the vessel, and tlie plaaiua may bo separated by decanta- 
tion. To the plaBiiiEi is added an exeees of pulverized chloride 
of sodium, when a, euft, pidpy substance is precipitated, which 
is plasminc. This substance, after deaiceation, beara a pro- 
portion of ab^^^It t^vcnty-five parts per thousand of blood. 
It is soluble in frum ten to twenty partfi of water, when a 
portion of it congnlfstea sud may be removed by stirring 
TvltU twigs or a bundle of broom-corn, iu the ivay in which 
fibrin is separated from the blood. The fibrin thus sepa- 
rated is calJcd by Denis, concrete fibrin, aud the eubstunce 
which remains in solution, dissolved tibrlu. By most writere 
of the present day, the dissolved fibrin of Donia is called 
metalbnmen, a name which we shall adopt. 

According to Denis, plasmine is a proximate principle 
of the blood, and, after extraction by the process just de- 
scribed, is decomposed into concrete fibrin and dissolved 
fibrin, or metalbumen. Having removed the concrete fibrin 
from the solution of plasmine, the metalbnmen is coagulated 
by the addition of sulphate of magnesia, ^\'hich dooB not 
coagulate ordinary albumen. The proportion of dried me- 
talbnmen in the blood is abont twenty-two parts per thoU' 
sand. The proportion of dried fibrin is about three parts 
per thousand. 

After the extraction of plasmine from the blood, another 
coagulable substance rentiiins, which is colled ficrine. This 
ie coagulated by heat, the strong mineral acids, and absolute 
alcohol, bot is not coiigulatod by utber, which coagulates al- 
bumen of the white of egg. Serine bears a close resem- 
blance to ordinary albumen, but is stated to be mnch more 

' Ouits, Mimoire nir It Mtip, Parii, 1909, p, ITS, 



QUANTITATIVE ASALTSIS. 147 

OBinotic' Its proportion, desiccated, in the blood ib abont 
fi%-three parts per thousand. 

"We cannot admit the esiatence of new coagulable prin- 
ciples in the blood, unless it be shown that the processes 
by which they are extracted do not involve decompoeition 
of normal proximate constitiionts. The processes just de- 
scribed do not seem to involve artificial decomiwsitioii. It 
is perfectly proper, in analyzing the blood, to prevent spon- 
taneous coagulation by the addition of the sulphate of soda, 
M this salt simply keeps the blood fluid witliout apparently 
chan^jig its oi^nic constituents, and the plasinine is simply 
precipitated, by the chloride of so<lium. It is evident, also, 
that the substance called, mctalbunien, being coagulated by 
sulphate of magnesia, is not albumen ; and serine also pre- 
sents some important points of difference from albumen. 
Admitting the existence, then, of plasmine and serine, it is 
important to understand clearly the characters of tliese prin- 
ci{de8 88 compared with what we formerly recognized as fibrin 
md albumen. 

Instead of fibrin and albumen in tlie blood, we now rec- 
ognize two new principles, in the nat\iral condition of the 
onmlating fluid, which are called plasmine and serine. The 
substance known aa fibrin is one of the products of deconi- 
poution of plasmine. Metalbumeu and serine constitute 
what was formerly called albumen. Fibrin is not a proxi- 
mate principle, bat is formed in the spontaneous decomiiost- 
tion, oat of the body^ of plasmine. Metallinnien is the other 
product of decomposition of plasmine. The fibrin of arterial 
blood has long been known to differ somewhat from the fibrin 
of Tenons blood, when the blood has been allowed to (coagu- 
late spontaneously. Arterial fibrin is insoluble in a solution 
itf chloride of sodium, which will dissolve the fibrin of ve- 
nous blood. 

I G.Am^ CMmU appligvte d la phifnologie, d la palholoffU ct A rhi/ffiiiie, 
Ftato, 1874, wnw L, p. BIS. 



THE BLOOD. 



Pejttones. — A cert^im quantity of nitrogeiiised tofttter, 
distinct li-om tlit priiiuplcs jiist deEfribeJ, lias been extracted 
from the bLuod, n'^hich is aniilogoue to ptrptuuc or albiimJDo&e. 
Thia 19 Geparated by coagulflting- the serum of the blood with 
liot iieetic aeid and tiUering, wlien tlie peptones pass throngli 
in the HUrato. These principlee are pmbably derived from 
the food. Their proportion in the plasma is about four 
parts, dried, per thousand, or twenty-eight parts, before 
desiccation. 

A small quantity of coloring matter exists in the plasma. 
If we separate tlie corpuscles fls completclj ns possible, tlie 
dear liquid still has a rcddish-aiuber color. This coloring' 
matter has never been isolated and studied. It is aanlogoua 
to the coloring matters of the red corpuscles, the bUe, and 
the urine. 

In addition to the organic nitrogenized principles which 
we have described, some authors recognize a eubstance called 
paraglubuline, or librinoplastie matter, and fibrinoj^ciiic mat^ 
ter. These are supposed to be factors of fibrin, which como 
together in the coagulation of the blood. They will be con- 
sidi^red in connection with the theories of coagulation. The 
6o-calle J a Ibii till nates of sodn and potasea have not been posi- 
tively e&tabliebed as proximate principlea. 



CHAPTER IIL 

COAGULATION OF THE BLOOD. 

General conBidentioDs — CharacterB of the clot — Cliaracters of the Beniin — Cir- 
cumstanceB which modify coagulation — Coagulation of the blood in the 
onanism — Spontaneous arrest of hemorrhage — Cause of the coagulation 
of the blood — ParaglobuUnc, or fibrinoplastic mutter — fibrinogen — Sum- 
marj of the properties and functions of the blood. 

The remarkable property in the blood of spontaneous 
coagalation has been commonly recognized almost as far back 
as we can look into the history of physiology ; and, since the 
discovery of the circulation, there have been few subjects 
connected with the pliysiology of the blood which liave ex- 
cited more oniversal interest ; but the ideas with regard to 
the cause of this phenomenon were for a long time entirely 
speculative. The first definite experiments upon this sub- 
ject were performed by Malpighi.' He was followed by 
Borelli, Ruysch, and a host of others, who hold conspicuous 
places in the history of our science, among whom may be 
mentioned, Hunter, Hewson, Muller, Thackrah, J. Davy, 
Magendie, Nasse, and Dumas. Wliile much labor has been 
expended on this subject, the final cause of coagulation is 
even now by no means definitely settled. 

The blood retains its fluidity while it remains in the ves- 
sels and circulation is not interfered with. It is then com- 

> Ualfiobiub, Dt Poli/po Cordii DUtertatio. — Opera, Londini, 1686, Tomua 
iL, p. 123, et Mtq. 



150 



THE BLOOD. 



ptteed, as we liave seen, of n clear plasma, liolding- corpufdes 
in Buspetisioti. Shortly nftcr tlte circuUtjoti ie iuternipted, 
or after blood is drnwn from the veseele, it coagiiliitce or 
*f eeU " into a jelly-like maes. In a few hours, we find that 
contractioQ has taken plaoe, and a clear, Btraw-eolorerl fiind 
line been cspresecd, the blood thue Beparating into a solid, 
portion, the crnBBamentum or clot, and a liquid, which is 
CHlIcd Bernm. The seniui contains all the demoDts of the 
blood except the red eorpuHclea and fibrin, which together 
form the clot. Coagulation takes place in the blood of all 
animals, commencing a variable tliuo after its remoTal from 
the vessels. In the hutuan subject, according to Knaee,' 
when the blood is received into & moderatelj-deep, smooth 
vessel, the phenomena of coagulfttion present themBelvee in 
the following order : 

First, a gclatinoiis pellicle forms on the surface, which 
occurs in from one minute and fort^*-five seconds to six 
minutes ; in from two to seven minutes, a gelatinous layer 
lias formed on the sides of the vessel ; the whole mass be- 
comes of a jelly-like coiisiBtencc, in from seven to sixteen 
minutes. Contraction then begins, and, if we wateh the 
surface of the clot, we see little drops of clear serum mak- 
ing their appearance. This iliiid increases iii quantity, and, 
in from ten to twelve hours, sepandlou is complete. Tho 
clot, ivhich is heavier, sinks to the bottom of the vessel, 
unless it contain bubbles of ga», or the Burfacc be -very con- 
cave. In most of the •warm -blooded animals, the blood coag- 
ulfltes more rapidly than in man. It is particularly rapid in 
tho daaa of birds, in eome of which it takes place almost in- 
stantaneously. (Ibecrvationa have shown that coagulation 
is more rapid in urterial thau in venous blood. In the for- 
mer, the proportion of fibrin formed is notably greater, and, 
He we have seen, the cliaracters of the fibrin are eoniewbat 
dift'ereht. A solution of cidoride of &odinm dissolves the 

' Hub', In W^uksr, /Zanc/iodWcr&ucA der PhifMU^ogv, BraunacliVeig, 1S4S, 
MU.,8.10S. 



CHARACTEBS OF THE OLOT. 



151 



fibrin of venous blood, but docs not dissolve tlic fibrin of an 
arterial clot. 

Tbe relative proportions of the serum and clot are verj 
TBriable, unless we include in our eBtimato of tbe SDrum that 
portion wliifh is retained between the luesbes of the clot.' 
As the clot (9 comptisod of corpuscles and fibrin, and aa these 
in their moist stale represent, in general tertns, about one-half 
of the bluod, it may be stnted that^ after coagiilatiun, the 
actual proportions of the clot and serum are about cr[ual. 
If we take simply the fienim which separates f-poutaneonslj, 
we have a large qiiantitj when the dut is deneelj contracted, 
and a very einaU quantity when it h loose aud eolV Ueuallyj 
tlio clut retains about une-Eftli of the serum. 

Charact^rt of tJte CU>1. — On removing the clot, after the 
separation of the Ecrum is complete, it presents a gelatinoua 

coneJBtence, aud is more or less firm, according to the degree 
of contraction which has taken place. As a genera! rule, 
when coagulation has been rnpid, tha clot is soft and but 
elightly contracted. When^, on the other band, coagidalion 
has been slow, it contrnctB for a long time and is much 
denser. "When coagulation is slow, the clut frequently pre- 
eenta what is known as the cupped appGavanec, having a con- 
cave snrface, a phenomenon wliicli depends merely on the 
extent of its contraction, It also presents a marked dift'er- 
once in color at its superior portion. The blood linviug ro 
mained 6uid for eome time, the red corpuscles eettle, by virtue 

' tt is ealifoaled. by Hilac-EJnarda that ihe clot retutns, in most iDstATHtefij 
«niL<-finh of Che entire Toliime of acnim. Le^n* mr la pfij/aii^ogii:, etc., Fails, 
1S57, inme r., p. 121. 

' Acofn-diug ti> Mnase (_ltv. r:il.. p. Il>5), ihi; following are the period* rei^iiircd 
for the congiilution o-F the blood iit eorae oF the Inferior amotalH.: 
In tttc Robbie, tlie bluod ■.■oiLgidutea Lu 1 minatc 
" Ox. " " 5 to 6 ninuttis. 

» &h«!p, « " li " a " 

" Pig, " " 3 " 

" Horse, " " 1 " 13 " 

" Dog, " ** B " 7 * 



153 



BLOOD. 



of their grenter ■R-eiglit, leaving a eolorlesB layer on the top. 
This is the hutfy-coat so frequently spoken of by authors. 
The buffed and euiipcLl appearance of the clot lias been eiip- 
posed to indicate an inflnmmatory condition of the circulating 
fluid ; inasmuch as the quantity of fibrin is generally in- 
creased in iiiflflimuntion, and the greater the quantity of 
fibria the more rapid is the gravltalion of the red corpuscles. 
Although this frequently presents itself in the Wood draira in 
infianimatloQS, it is by uc meaiis pathognomonic of this cou- 
dition, and ia liable to occur whenever coagulation is slow, 
or retarded by (irtificial uicans. It ia always present in the 
blood of the horBe. Examined niicroecopieally, the bufty- 
coat preeentfl fibrils of coagulated fibrin with some of tho 
white eorpiiBclcs of the blood. On reniovii>g a clot of ve- 
nous blood from the scrum, the upper surface is florid from 
contact with the air, while the rest of it ia dark; and, on 
making a section, if the coagulation have not been too rapid, 
the gTiivitation of the red coqmscles is apparent. The eec- 
lion, which is at first almost black, goon bcfonius red from 
contact with the atuLogphere. If the clot bo cut into small 
pieces, it will undergo farther contraction) and express a 
part of the euntsiued eenim. If the clot be washed uudor 
a strciini of water, at the same time kneading it with the 
fingers, we may remove almost all the red corpiist'lcs, leaving 
the meshea of fibrin, which, on microscopical examination, 
will present the fihiilktcd appearance to which we have 
already referred. Tliis. h a moihod sometimes employed tor 
the uxtractioii of the fibrin. It was in tins way that fibrin 
was isolated by Malpighi, who made the firet experinienta 
which rendered it probable that coagulation of the bluoti 
depended upon this principle. In a lew days, as the result 
of putrefaction, the elot sometimes soltens, mi-^ea with the 
aerum, and the blood rcgaine ita fluidity, 

CJia/'fwtfi'a f>f tAe Sera/n. — After coagulation, if the wrum 
be carefully removed, it h found to be a fluid of a color 



COACrLATEV'O PHIKOIPLE OF 71IE BLOOD. 



153 



vaTving frotn a Jight fimber to quite a deep, but clcnr red. 
TluB depends iipuu a peculiar coloring matter Avliidi has. 
never been ieolatetl. Tlie specific gravity of the Benira is 
about 1028, Bomewliat Ifi^s than tbat of tlic; entire luaes oi' 
blood. It contHins all the prineiplefi found iii the plnEina, 
or liqnor eangiiiiiis, with the exeeplion of the tihrin. It fan 
hardly be c.illed a physiological Jluid, as it is formed only 
after coagulation of the blood, and tiever extfits isolated in 
the body, The effusions which are commonly called eerum, 
slthcDgh they reeemble this Gwid In bomc particulars, arc not 
identical with it, being fornted by a process of transudation 
rather than separation fi'om the blood, as in coa|i:;iilalion. 
The Bcnim must not be confounded with the plasma or 
liqnor sanguinis, which is the natural clear portion of the 
blood. 

Coaffvlatinff I'rineijtle of the Blood. — Accinainteil, as 
we are, with the jjroperties of tibnu, it ie evident that tliia 
principle Is the agent which pro ducea coagulation of the blood. 
In fact, whatever tongulatea spontaneously is called fibrin, 
und whatever requires some agent to produce thia change of 
eonsisteiice is called by another name. But, before the prop- 
erties of fibrin were fully understood, the question of the 
coagulating principle was a matter of nnieh discueelon. 
Matpighi was probably the first to isolate fihrin, which he 
did by wa&hing the clot En a stream of water, which removed 
the eorpiiecleB and left a whttiBh, fibmus net-work.' Hit ex- 
periments are set forth in an article in which he attempted 
to show tliHt the eo-called polvpi of tLe heart were formed 
of fibrin, thongh it was not then called by that name. These 
obeen-ationB were eoon <!ontimjed by others; and it then 
became- a ipie&tion whether this substance cxistod as a fluid 
in ilie liquor ennguiniF, or was furnished by the coipusclee 
after the removal of blood from the veaaele. This was de- 
cided bv newsoBj whose simple and conclusive esperimenta 

' MaLPiQaics, Oyjera, Londini, IfiBO, Tomus il., p, 123, rf wj. 



154 



THE BLOOO. 



leave no donlht that coa^lntiun oi'tlie bluo'l is due tu fiLrin, 
and that tliis Bulietaticc is entirely diBtiRct from, and inde- 
pendent ofj the corpuscles. TLis observer, taking advautage 
of the property poeseesed l>y certain saline subf^taneea of pre- 
T^Btrng tbe coagulAtioD of tUe blood, wae the firet to sepa- 
rate the liquor fiangiiinie from the corpuBcles. He mixed 
fresh blood with a little eulpbate of soda, wbich. prevented 
cuugulatiori, and, after the nuxturc bad been allowed to stand 
for a time, tlic eorpuecles gravitated to the bottom of the 
vessel. The clear flnid was then decanted and diluted with 
twice its quantity of water, when the fibrin becftme cuagn- 
lated.' Another experiment is etill more conclusive ; aud, 
as the credit of having first sefmrated the coqiuscies from 
the plasma and demon stm ted the congidability of tbe latter 
is by some aecribed to Miiller, we shall give it in tbe author's 
own words : 

*' Immetiiately after killing a dog, I tied np his jugular 
veins near tbe st-ernuiit, and bnng his bead over tbe edge of 
the table, so that tbo parts of tbe veins where tbe ligatures 
wore might be higher than his head. I looked at the veins 
from tirae to time, and observed that they became trans- 
parent at tbeir npper part, the red particles snbsiding. I 
then ninde a ligature npon one rein, so as to divide the trans- 
parent from the red portion of tbe blood ; and opening tbe 
vein, I let out the transparent portion, u-hich was atill fluid, 
but coagulated soon after. On pressing this coaffuhim, I 
found it contJiined a little serum, Tbo other vciu I did not_ 
open till after tbe blood was congealed, sud then I fo 
the upper part of the coa^ulum wliitish like the crust 
pleuritic blood."" 

Kotbing could more conclusively demonstrate that coa 
nlatiim of the blood depends upon a coagulating principle 
in tlie liqnor snnguiTiis, tbim this simple expcnmcnt. It 
also beantifully illuBtratcs the formation of tbe buSS"-cotll 

' IlEn^^, J^rprrimenlal Intjuiru*, LoodoD, 1780, p. 19. 
' iiBWBOS, op. dt.f p. 37. 




CIECUMSTASCES 'WHICH MOl'IFY CIRCULATION. 155 

Tlio facta thus demonstrated by Heweon were confirmed 
by Muller, in 1832. Ho succeeded in 6C])nrating the plasma 
from the corpuecles in the blood of the frog by simple filtra- 
tion, first diluting it with a saccharine solution. The great 
uze of the corpuscles in this animal prevents their passage 
tiirough a filter, and the clear fluid which is thus separated 
soon forma a colorless coagulum.* 

From these observations, it is evident that the coagula- 
tion of the blood is duo to the formation of fibrin. Coagu- 
lation of this substance first causes the whole mass of blood 
to assume a gelatinous consistence ; and, by virtue o( its con- 
tractile properties, it soon expresses the serum, while the red 
corpuscles are retained. One of the causes which operate 
to retain the corpuscles in the clot is tlie adhesive matter 
exuded from their sui-facc after they escape from the ves- 
sels, producing the arrangement in rows like piles of coin, 
vhich we have already noted under the head of micro- 
scopical appearances. This undoubtedly prevents those 
near the sorface from escaping from the clot during its 
oontraction. 

Oireumgtanoes which modifij Coagnhition out of the Body. 
— The conditions which modify coagulation of the blood 
have been closely studied by Hewson, Davy, Thackrah, 
Bobin and Terdeil, and others. They are, in brief, the fol- 
lowing : 

Blood fiowing slowly from a small orifice is more rajndly 
coagulated than when it flows in a full stream from a large 
orifice. If it be received into a shallow vessel, it coagulates 
much more rapidly than when received into a dce}> vessel. 
If the vessel be rough, coagulation is more rapid than if it 
be smooth and polished. If the blood, an it flows, be received 
on % cloth or a bundle of twigs, it coagulates almost instan- 
taneously. ■ In. ahort, it appears that all circumstances which 
finTor expoBUfe.of the blood to the air hasten its coagulation. 

I SIdkixbb, Manitdde I^yaioloffit, Vaiia, 1B9I, lome i., p. 96. 



156 



Tllli: BLOOD^ 



Tlic blnod will coagulate more rapidly in a vatmum than ml 
the air. 

Coiigulation of the hlood is prevented bj rapid freezing, 
Irnt ftfterTTJird it takes place when the fluid is carefully 
thftwed. Between 32* and 140" Fahr., elevation of tem- 
pci"atare incroaecs the rapidity of coagulation. According 
to Kidiai'deon, agitation of the blood in closed vessels r»-| 
tards, and in open vessels hastene, coa^idjition.' 

Various ehemieal substances retard or prevent coagula- 
tion* Among them we may mention the Iblluwiug: soln- 
tions of potash and of soda ; carbonate of soda ; carbonate 
of aniraouiri ; carbonate of potjisli ; ammonia ; and sulphnte 
of soda. In the menstrual flow, the blood is kept fluid by 
inUture with the abundant socretione of the vaginal mucous 
membrane. > 



Coafpdation of the Blood in the Organism. — The blood 
eongnlateg in tbe vessela after deatb^ though less rapidly than 
when removed from the body. Ab r geneiiil proposition, itj 
may be stated that this takes place in fi-om twelve to twenty- 
four houra after circulation has ceased. Under these circum-| 
Btflnces, it is found chiefly in the venous system, as the ap-j 
teries are generally emptied by post-mortem contraction of 
their iimgcular coat ; but, in the veins, coagulation ia slow 
and imperfect. Coagiila are found, however, in the left side 
of the heart and in the aorta^ but tlicy are ninch smaller than 
those found in the right side of the heart and the large veins. 
These coa^ila present the general characters we have a!ready| 
described. They are frequently covered by a soft, M'liitisl 
flhn, analogous to tho bufty<*oat, and are dark in their in- 
terior. 

It was supposed by John Hunter that coagulation of the 
blood did not take place In anitnaU killed by UghtTiing or 
by prolonged mnseidar exertion, as when bunted to death ;*j 

^ IlrirTKii, Letlura on tAe J'rinf^a cf Surstri^t FluUdelphiK, 1B39, p. SA. 



OOAOULATION IN TOE ORGAKISM. 



15T 



but it appears frfim tlie observations of otliers tlmt tliib view 
IB not correct. J. Djivj reported a case of death by ligiilniiig 
where a looae coagulmn was found in the lieart twenty-four 
btmrs after. In this oase, decomposidon Tvas vory far ad- 
TAucGf], mid it is probable that the coagula b»d become less 
firm from that cauee. Hia obeervations also show that coag- 
nlation occure aftpv jwtsouing by hydrocyanic acid, and in 
animalB bunted to detitli.' 

Coagulation in difl'erent parts of the vascular ayBtein is 
by no iiicnns iinnsual diirinj^' life. In the heart, we same- 
timca find coag:uIa wliich bear evidence of having existed for 
BOTne time before death. These were called polypi by some 
of the older ivriters, and are often formed of fibrin almost 
free from red corpneeles. They generally occur when death 
U very gradiiai and the circulation continuefi for some time 
with g^reatly -diminished activity. It is probable that tx email 
coaguluin is Jiret formed, from which the CLirpnscles arc 
washed away by the current of blood ; that this becomes 
larger by farther depositions, until we have largCj Tcrmicular 
, masses of fibrin, attached, in some instances, to the chordje 
*tendme*e. Clots formed in this way may bo distinguished 
from those formed after death, by their whitish color, dense 
consistence, and the closeness with which they adhere to the 
walls of the lieart. Casee have been reported by Richard- 
son and others, where concretions of this kind' extended 
from the cavitieg of the heart far into the large vessels. It 
IB also stated by Richardson that they sometimes bocomG 
partly organized and connected with the tifisno of the heart; 
but we have seen that accidental deposits of fibrin never, 
under any circumstaucea, become transformed into organ- 
izeil struL-tures. 

We need only enumerate 6onie of the other conditions 
under wliich the blood coagulates in the vessels, as this sub- 
ject belongs rather to pathology than to phyeiology. Coag- 

' Datt^ Rnmirekf, Pkgtiato^Kol and Anatainital, London, 1930, vaL iL, 
p.fV, rfn?. 



158 



THE BLOOD. 



uUtion may be said, in general terms, to occur as a con- 
ditiou of stasia. WTken a li«ature is applied to an artery, 
the vessel becotuca tilled with a coogulmn np to the site of 
tlio firet branch wKiicli ifi given off, whatever be its situation. 
Ill applying; the lip;ature, the clelimte inner coat ia ruptured, 
and the Bhrede, whioh curl up in the interior of the vessel, 
Boun become covered with a Iiiyer of congiihited blood, which 
thickens until the whole vessel is filled. In caees in which 
the flow of blood becomes arrested or very much retarded, 
as in varicose veins of the extremities, the enlarged veins in 
lin-morrhoida, etc., theec vessels may become oLUterated by 
the formation of a clot. In some aneurisms, the retardation 
of the blood-ourrent prodnces spontaneous eure by the depo- 
sition of snccessive layers of fibrin next the walls of the di- 
lated vessel. A knowledge of this fact haa been made lue 
of in the treatment of aneurism by eouipression of the artery 
which supplies it with blood. Many cases are on record, 
wdiere this has been continueil for a. number of hours, and & 
cure effected. 

Bodies projecting into the caliber of a blood-vefisel soon 
become coated witli a layer of fibrin. Rough concretions 
about tjje orifices of the heart frequently induce the deposi- 
tion of little mafisea of fibrin, whicli sometimes become d&- 
tiiched, and are carried to various parts of tho circulatory 
system, as the lungs or brain, plugging up one or more of 
the sniailer vessels. The experiment has been made of pass- 
ing a threiid through a small artery, allowing it to remain 
for a few honrs, when it is found coated with a layer of 
coagulated fibrin. 

Blood generiUy coagulates when it is effused into the 
areolar tifidite or into anyofthe cavities of the body ; althongh, 
effused into the serous cavities, the tunica vaginalis for ei- 
amiilu, It hitri been known to remain fluid for days and even 
weeks, and coagulate when let out by an incision. In the 
Graatian folUclee, after the diecharge of the ovum, wo some- 



6POSTA>-Eors aekebt of ij.aaioaRHAOE, 159 

times Itave the cavity filleil with blood, ayLIcIi forms a clot, 
and is slowlj rtmovyd hy the process of Jibsorption, 

Coagulatiou thus takes pkce in the vesBela as the result 
of stasis or very great retanlatiou of the eirciilntion, and iu 
the tissues or cavities uf the body, whenever it is accidentally 
ej^nacd. In the latter CMC, it is generaily removed ip the 
course of time by absorption. This takes place in the fol- 
lowing \vay: Fir&t, we hare diBappearaucc of the red cor- 
puscles, or decoloration of the clot, and the librin i& thun 
the only element which remains. Thia Lecomee reduced 
from a tibrillatcd to a granular condition, softens, finally be- 
come* aniui-plious, and is abeurbe*! ; filthnug'h, ■when the size 
of the clot is considerable, this may occupy weeks, nnd even 
months, and may never be completely clibcted. Effused in 
thia mnrner, the constituents of the blood act as foreign 
bodies; the corpuaclcs cease to be organized aaatomical 
elements capable of self-rcgcntration, break down, and are 
absoriied. The fibHo which remains und(?rgocs tlie eaujc 
pfocess ; the Btages tlirongh which it paeeea being always 
those of decay, and not of development. In other words, it 
is incapable of organizntion. 

Office nf ths Coatjulaii&n of the Blood in arresting 
Hci^tiorrhftge. — The property of the blood under considera- 
tion bae a most important office in the arrest of bjemor- 
rliage. The effect of an absence or gi'eat dtniiQUtion of the 
coagulability of the circulating fluid ia exemplified in in- 
stances of what is called the liEemorrhagic diatbeeis ; a con- 
dition in which elight wounds are apt to be followfd by 
alarming, and it may be fatal liaMUorrhiige. Th's condition 
of the blood is not cbflrncterizC'd liy any symptoms except 
the obstinate flow of blood from slight wonnds, and may con 
tiime for years. In a case wliicli came under our observation 
a few years since, excision of the tonsils waa followed by 
bleeding, which continued for severnl days, and was ar- 
rested with great difficidty. On inq_uiry, it was ascertained 



160 THE BLOOD. 

that the patient, a young man about twenty years of age, in 
other respects peiTeetly healthy, had been subject from early 
life to persistent hiemorrhage from slight wounds. In re- 
viewing the functions of fibrin, we find that apparently its 
most important office is in the arrest of hiemorrhage. The 
degree of coagulability of the blood depends on the quantity 
of fibrin, but its proportion has not been shown to bear any 
definite relation to the vigor of the individual, nor to the 
processes of nutrition generally. The necessary and con- 
stant variations in the organic elements of the blood, which 
are the result of insufficient alimentation, exhausting dis- 
charges, or diseases characterized by impoverishment of this 
fluid, are observed in the albumen and red corpuscles, and 
not in the fibrin. By this it must not be imderstood that 
the quantity of fibrin is not variable. It has been found, 
for example, by Andral and Gavarret to be pretty generally 
increased in the phlegmasioe ; but it bears no relation to the 
richness of the blood. Its proportion is not increased al- 
ways in plethora and diminished in aneemia ; and in fact it 
has been found by Nasse to be increased in animals sufler- 
ing from hunger.' After haemorrhage, which diminishes 
the corpuscles and albumen, the fibrin is generally increased ; 
80 that the fact of loss of blood, diminishing the force of the 
heart and increasing the tendency to coagulation, has an in- 
fluence in the arrest of the flow. 

Circumstances which accelerate coagulation have a ten- 
dency to arrest hemorrhage. It is well known that expos- 
ure of a bleeding surface to the air has this effect. The way 
in which the vessel is divided has an important influence. 
A clean cut will bleed more freely than a ragged laceration. 
In division of large vessels, this diflerence is sometimes very 
marked. Cases are on record where the arm has been torn 
off" at the shoulder-joint, and yet the haemorrhage was, for a 
time, spontaneously arrested ; while we know that division 

' Nasse, in WiONU, Handieorterbuck der PhymologU, Bnmiuohwcig, 1842, 
Bd. i., S. 143. 



SNTANEOUa AKEE8T OF H^atORBHAQS. 



161 



of an arter_v of smaller size, if it be cat acroBs, would be fatal 
if left to itself. Uiitlcr tln^^ee tircnmstances, the internal coat 
is lorn iii alireds, which retract, their curled enda projecting 
liito the C'filiber of the vessel, and have the sarao effect on 
the coagulation of Wood aa a bundle of twigs. In laceration 
of BTich H larg'e vessel as the axtllai-y artery, the arrest caouot 
be pernianeut, for, as soon a9 the system recovers from the 
sbockj tlie contract ions of the heart will force out the coagu- 
lated bluod whi^rb lias closed the opening. 

In our study of the ftinctionB of the body, we shall con- 
tinually see evideuiees that Nature, not content with simply 
providing for the ordinary waiita of the Byetem, baa made 
provision, for extraordinary occurrences and accidents. A 
atrikijig example of this is the function of tibrin. All tbo 
ordiiiary operations of the body g^o on perfectly well in a 
person affected with the Iweuiorrhagiy diathesis, in whose 
Wood the fibrin is wanting ; ' ami, as wo have already seen 
in treating of tranefusion, the vivitpng effects of defibrinatcd 
blood arc equal to those of hlood which contains all its con- 
stituents ; yet it is provided that, in hffimorrhage, the blood 
solidifies and closes the opening in the veescla, if they he not 
too large^ Kature often makes attempts to cure anenrJams, or 
btemorrboids, by the same process ; and hence does not ob- 
literate the ves^eU by an org^anized substance, which would 
be capable of seli'-regeneration and always remain as port of 
the body, but throws out a temporary phig, whicli h des^ 
tincd to be removed, partially, if not completely, by ab6ori>- 
tion. The process of coagulation of the fibrin of the bluod ia 
eflsentially different from that of tbo gradual effusion of plas- 
tic lymph by wbieb injuries are repaired. Individuala suffer- 
ing' tuider the boBniorrliagic diathesis are not deprived of 
the power of repalting injuries by means of plastic ejcudft 
tions from the blood, though the blood contain no fibrin, 

' Wp are foree'l to *^y^^ wnstautly of flbrin aei a oonslituenV of tbo blood ; 
bm W4 mvau \>j bldod (.'omiuumg fibrin, Mood in wbivEi fibria is foiJDed undef 
aerUia conditiuaE, to wlilcb i*e have already illudcd. 



162 



THE BLOOD, 



and hsemorrlinge is not arrcBted until the procesB of repair 
has closed the openings in tho vessels, or tre linve dosed 
them hy the effect of our styptics. We likewise see tliat^ in 
tlie lower animalsj wlio have not the means cf artifiuiallj ar- 
reeting- hffinorrhag'e, its spontaneous arrest is more effcgt- 
ually provided fiir by a more rapid coagulation of the blood 
From the foregoing considerations, it is evident tliat tlic 
remarkable pIienoincTion of coagnlation of the blood, wliich 
haa so much engaged the attention of iihyeiologifits, has 
rather a mechanical than a vital fiinciion ; ff*r its fhicf office 
is in tiie arrest of hiemorrhnge. Coagnlation never takes 
place in the organism, itnlesa the hlood be in an abnormal 
condition with respect to cirenlntion. Here its operntiona 
are niniuly conBcrvative ; but, ae almost all coneen-alive 
processes arc sometimes pcr%"^erted, clots in the body may 
be prodnctive of injury, as in the instances of cerebrnl aj>o- 
plesy, clots in the heart occurring before death, tLe'detach- 
ment of emboli, etc. 

Cause of the CoagiilMion of the Blood. — If wc adopt the 
views regarding the composition of the blood which involve 
the production of fibrin as a result of the dceompoaition of 
phismine, we must chnnge in ioto oht ideas of the cause of 
tho coagulation of the blood. According to our present 
views, fibrin does not exist aa a proximate principle, and 
plasmine is never decomposed in the body^ under perfectly 
normal conditions; but, if the blood be dra^tn from tho 
body, effused from the veesela, or the circulation be arrested 
for a certain time, plasmine is decomposed, fibrin is formed, 
and the blood coaguiatei. 

In the first edition of thia volume, written in 1864, we 
diacu&sed the question of the cause of the coagulation of the 
bloCrfl quite fnlty ; but fibrin wfls then generally regarded as 
a proximate principle itself, and not aa a product of decom- 
poEition. The theory that we then adopted was ibe one 
proposed by Eicliardson, in 1856 ; viz., that the Wood nor- 



OAUSE OF C0AOin.ATI0N OF THE BLOOD. 



163 



inallv contains a Bina]I quantity of ninmonia, tlie preseiico 
of wliicli Icecjjs the filirm in a lij|uid stfttc ; that ammonia ia 
constiuidy being taken up by tlie blood from tbe tiasiiM and 
exhaled by the lungs, and that, -w-hen the circulation of tlio 
blood is arrested, or when the blood is effused or ch'fiwti 
from the vcsEeU, nmmoaia is exhaled and coa^lation takes 
place. This theory has been fonuoUy abandoned by Kichard- 
son, who adiiere&f however, to tlie accuncy of hi& oxperi- 
niunts. JS these experimeiiiB be entirely reliflble, they eecm 
to prove the theory ; but it ia stated by Kobin, tliat, using 
chemical proceseea that will deteut y.jnfj.innr "**" aimnonia, 
not a trace of this substance ia to be found in the blood, 
that a Binall quantity of ainmoniiL added to the blood does 
not prevent coagulation, and that the blood eeenrod against 
evaporation will nevertheless coagulate,' The chemical es- 
perimentB of Riehardbou were not very delicate, and the 
objections to them, niado by Robin, are probably well- 
founded. We are Justified, therefore, in abandoning; the 
theon,' that coagulation of tho blood ia due to the ovuliitioti 
of ammonia. 

We raay talie the aaine jwsition with regard to the older 
theories of coagnl;ition, wbioh were nearly all vague and 
unaatisfactory. Tlie idea that exposure to the air ia the 
csTisc of coagulation, which was heM by Hewson, is dis- 
proved by the einiple thct that coagulation takes place in a 
vflcuiLm. The vital theory of Hunter, which was adopted 
by most physiologists of his time, is too indefinite for dis- 
cns&ion at the present day^ and realty expresses ulfer want 
of knowledge on the subject. The theory- that motion is 
the cause of the fluidity of fibrin in the body, is disjiroved 
by the fact tliat violent agitation of the blood out of the 
body does not prevent coagulation ; and thus it i& with 
nearly all the theories that have been advanced. 

The idea which we have to present does not expUiin why 
the blood coflgulatee, but it gives a certain notion of the 
^ RoBiv, X/tfprtt wr Ut Auwiewn, Paris. ISV4, p, 1V8. 



164 



BLiTOD. 



probflbb ccjiidEtlous under wbtcU plasmlne exists in tlie cir- 
culating fliut.1, 

PJafiiiiine, circulating in tlie blothJ-veseeU, uiider uormal 
conditions, is a liquid, and its decompoeition into metalbu- 
inei) and fibrin, is abuorninl. Plasinine is undoubtedly an 
important uatritive principle, and 3s coustantly undergtiing 
change aa it is used in tlie Tintrition of the nilrogenized con- 
stituents of tbe various tissues atrd org;an3, the matcrinl thus 
expended being restored by tbe nitrr.genized constitnents 
of tbe food. It is, therefore, like otbcr nitrogenized con- 
stituents of tbe organism, In a condition of constant meta- 
morphoeie ;: and all that we can say is that, while in (bia 
coiulition, getting material trom some parte and giving ofl' 
mattera in otbpre, it does not undergo those dcconiposing 
cbangM which are obecrved when it is elTnecd, drawn from 
tbe body, or tbe circulation is arrested, which involve coag- 
ulation of the blood. 

Tbo above expresses nearly all that we positively know of 
thecauie of tbe congulation of tbe blood ; but the qncstion in 
fact reduces itself to the rather unsatisfactory pniposition, 
that tbe blood coagulates because, when its nitrogcnized pria- 
clplee are removed from tho^e constant molecular clmngeB 
which are characteristic of tbe claea of nUrogenized prin- 
ciples as they exist in the living organism, deconi]K>sition 
takes place, which results in the procbiction of a coagulating 
matter. It is hardly to be expected tbnt ])hyBiologiista wyuld 
be satisfied with thiH, which is indeed little more ibnn a con- 
fession of ignorance; but it must be remembercc] tliat we 
are very little acquainted with the niolccnlar changes taking 
place constantly in the living body. When we understand 
these more thoroughly, we may obtain a better knowledge 
of the causes of coagulation of the blood, cadaveric rigidity 
of miiedes, and other cliangee which take place when the 
proccBses of nutrition cease. 

Within the last few years, A. Schmidt (1861) has pro- 
poBcd a theory of coagulation wliich involves the coming 



CiUBl: OF TOA0OLATICOT OF THE BLOOD. 



165 



togetlier of certain principlcB called fibrm-fac-torB. This 
tbeory lins been adopted and more or less modified by 
KiUiiie, Vii'cbow'j and otliere. If bJood-pIasma^ rendered 
neutral ivith acetic acid, be diluted wltb ten times ite vol- 
ume of irater at' 33* Fdhr. and t!ien be treated with r cur- 
rent of carbonic-acid gas, a flociculent precipitate ie foniied, 
wliich lias been called paraytobidino, or fibriiiopketic mat- 
ter. This Gubstanc'O may be tlissulved id water eontaiuing 
air or oxygen in eohition. At'Jer tins preci])iEato Las been 
eeparated, if the clear litjiiid he ililuted witli about twice its 
Tohime of icc-t-old water and be iigain treateri for a long 
time witb a current of cnrbonlc acid, a viscid Bcuni is pro- 
duced, whicL has been called fibrinogen. A small quantity 
of filirinogcn added to a Boliitlon of paraglobuline produces 
CoagnIatt<in of a substance like fibrin. More recently, a 
third principle, a ferment, has been described by Scbmidt, 
"which he fonsiders necessary (o the formation of fibrin.' 

It is very questionable whether the fiubetances called 
parflglobiiline and fibrinogen exist in (lie blood a& peculiar 
principles. Robin considers parag-lobnlinc as identical with 
jnetalbnmen, which is itself one of the products of the de- 
composition of plasmine. It is true tliat the so-called fibrin- 
ogen, added to the liquid of hydrocele or other Bcrosities 
not &pontanconsly coagulable, produces coagulation, but this 
occurs, thoiigli more slowly, vrhen the scrum sepamtcd from 
the coagulated blood is added to these liquids, 

It ift more in accordance with our positive knowledge to 
state that we uudcrRtanJ nothing with regard to the cause 
of coagulation of the blood beyond the fact that plrifniiue, 
when rerocivcd from its nonnal condition in the circulation, 
docompoBCB into eoagnlatinj; fibrin mid metalbumeji, than 
to admit the existence of fibrinogen, a ferment, and para- 
globuline, all of which may be products of decompoaition. 

' Fr>i- a Tull diflciisAion ortlii? itiiTi-'retit thcoti^a of coiLgiilation, nich ciimionfl 
of tbc origitinl mcnioira of Sthmidt, Eubn«, and Othcm, the rcbdcr ifi Kftcrtd tO 



106 



THB BWKW. 



It is a curiouB fact that Iceeli-tlmmi hlood remaine fluid 
in the body of the flniinal. Rit'bitrd&on Iibs observed, also, 
that the bloud flowuig ft'om a kech-bite presents the same 
persistent fluidity, which explains the well-known f«ct that 
the insignificant ivonntl f,nvea rise to ooneiderable hspiuor- 
rhai^e. On thia point he has made the following curious ex- 
periment : 

" After the leech was removed from the arm, the wound 
it had produced continued to give out blood vorj freely. I 
caught the blood thus flowing at different intervals^ allowing 
it to trifklc into teaspoonB of the same size and ehape. The 
results were curious. The blood which was received into the 
first spoon, and which was collected immediately after the 
removal of the leueli, was dark, and showed the same feeble- 
ness of coiigulation as the blood taken from the leech itself. 
Another portion of blood, received into a second spoon five 
minutes later, coagulated in twenty-five niimUes with mod- 
erate tinnncBB. A third portion of blood, ciinght ten min- 
utes later still, coaguiati'd in eig'ht miimtea ; wliile at the 
end of half an hour the blood which still flowed from the 
wound coagulated firnilyj and in tine red clots, in two min- 
ntos. TJltiinatelj the blood coagulated as it slowly oozed 
from the wound, so that the wonnd itself was sealed up.*** 

The exiBtent'o of projections into the caliber of vessels, 
or tlie passage of a fine thiead tlirouph an artery or vein, 
will deterniiue the formation of a small coa^ulnm npon the 
foreign substance, while the circulation is neither interrupted 
nor retarded. These fni?tB demand explanation ; but all we 
ean say with regard to them ia, that, in the present state of 
our knowledge, explanation is difficult, if not impossible. 
The process, under these circumstances, cannot he suhje^rted 
to direct experiment, as in the case of the blood coagidating 
out of the body ; but a reasonable inference ia thut the for- 
eign Substance arresta the circulation of a certain portion of 
pla^mine, which then undergoes decomposition. 

' RicaABPsoM, CMffvlatioH of the Blood, Loadoa, 18B7, p. 207. 



BDOtABT OP ntOPmriTES Aw> miCTIOSS. 



167 



Ihiring- congulaticin, fibrin asanniea & filamentouB forro, 
presenting, under the microscope, the appearance of recli- 
linear fibrillte. These fibrlllae gi'aditnily iucrease in number 
and, as contrflctJoTi of tlie clot oecure, become irregularly 
crossed. They are al'ways Btraigbt, however, and never 
assume tlie iindnlating jippearanco characteristic of the white 
fibrous tissue. The appearance just described does not in- 
dic-ate a procees of organization^ Whcu fibrin is effused 
into any of the tissues or or^pine from njpture of vesselsj it 
acts as a foreign subetance, anil, in time, becomea entirely 
or in part absorbed. The ;^radiial production of membranes 
of new formation, as one oi'the results of iiifiammaJion,tbeBe 
becoming organized, is entirely different from eudden ha;mor- 
rbagic efftiBiopa. 

Tlie blood of the renal and hepatic veins, capillary blood, 
and the blood whieh passes fi-om the cajnllary system into 
the veins after death, does not generally coagulate or coagu- 
lates very impeifet'tiy ; in other "words, llieae varieties of 
blood do not readily form fibrin. The reason of this pecu- 
liarity is not known ; but the fact afl'orde a partial explana- 
tion of the normal fluidity of the blood ; for this fluid, pass- 
ing over the entire course of the circuhition in about thirty 
seconds, seems to be constantly losing ite coagulability in its 
passage through the liver, kidneys, aitd the general capillary 
fStem, as fast as its co-tgulabihty is increased in the other 
of the circulatory syetem. Taking into consideration 
~the rapidity of the circulation, it is evident that the blood 
cannot coagulate while the normal circulation ia maintained, 
and while it is nndei-going the constant changes incident to 
general nutrition. 

JSummanj of the Properiies and J^undlons of the Blood. 

The blood, constituting as nearly as cftn be estimated 
one-eighth of the weight of the body, is the great nutritive 
fluid, its presence being necessary to life, and its normal 
couBtitutiuu and circulation, cBsential to all the functions. 



168 



THE BLOOD. 



ATiatomtcallyjits most important elements nre a cle*r 
plasma aiiil tie red coipuscles, these existing; in ftliomt ci^tial 
proportions. Tbe t:liief office of tlic corpuscles seeiue to be 
to carry vxygeu from the lungs to the tisBnes. Their pres- 
ence is iinnioiliately essential to lile, and their normiil pro- 
portion, essential to UeJiUh. They are organized anntomicftl 
elementaj cajiable of self- regeneration from principles con' 
tained in the plasma. They contain all the principlca which 
exist in the plasma, with the diflerence that the jdasmine 
and serine of tlie latter are replaced by globnline^ and a 
coloring matter, hrpmaglobine, is superadded. The iilasma 
eeenia to be- the part t-hietly cmplojcd in the nourishment 
of the tissues, some of which, as cartilage, do not receive 
any of the corpn&cular elemeitte of the blood. 

Chemieally, the plasma contains the elements whicli are 
necessary for the regeneration of all parts of the body. 
These are continually being used up in nutrition, but are 
replaced hy the absorption of articles of food after tiiey have 
undergone digestion. In the dcjiosition of new matter in 
the regeneration of the tissues, the organic aad inorganic 
constituents of the plnt^ma are deposited together. 

The or^pinic constituents are used in the nutrition of the 
organic nitrogenized elements of the tissues. Their diminu- 
tion in the blood to any considerable extent determines de- 
fective nutrition. It is probable that all the other organic 
nitrogenized principles are formed from them. 

ltd peculiar property of epontaneoua coagulation gives to 
the blood a most irajjortant conservative function in the 
arrest of hteniorrhage. The proportion of fibrin formed in 
the blood during coagulation bears no relation to the func- 
tion of nutrition. Its orcaBional absence only induces ob- 
stinate hietnorrbage on the division of vesselB, even of very 
etnnll size. 

Fnt, wliieh exists in small quantities in the blood, And 
sugar, which exists only in certain parts of the circulatory 
Byateni, disappear in the organism in a way which i& not at 



SCiniAET OT raoPEKTTES AND FCKOnOJfS. 



169 



present understood. They are concerned in, and necessary 
to, the processes of nutrition ; but the exact nature of their 
fnnction is unknown. 

.The inorganic conetituents of the body are found la vary- 
ing proportions in the plasma, and have varied functions. 
Their presence tendi to preserve the proper c-onstltHtion of 
the corpuscles^ "vrhich arc dissolved in piu-e water. 

Tlie water which does not enter into the constitution of 
the plaemine and serine eervea to hold the vanoas salts in 
solution, and cannot vary much in quantity from a certain 
Btanilard. 

Some of the iuorganic salts, the chlorides particularly, 
Beem to reg^ilftte, to a certain extent, the processos of nutri- 
tion, are found most abundantly in the fluJOs, and appar- 
ently do not form a very essential portion of tiie ti&euee 
theuiseU'es. A tendency to an excess in the Llood is re- 
lieved by discliarge from the eyetem. and a dimitjution is 
occompanieil Ijy certain indefinite disorders in the general 
processes of nutrition. 

The all;aline earlionatea have a tendency to prcHorve the 
fluidity of tlie blood. 

Some of ihe inorganie salts, such ae the phospliate of 
lime, are important elements entering into the constitution 
of the various tissiice. They are most abundant in the eolida 
and semisolids of the body ; and, wlien their introduction 
with food is prevented, we liave certain definite changes in 
the const it Lttion of some of the tisanes. 

As already remarlced, tlie inorganic principles are necea- 
sary to, und participate in the performance of the pliysio- 
logicftt functions of orgisnic principles. 

In addition to constituents already noted, the blood con- 
tains brge quantities of carbonic acid, which is eliminiited 
by the limgSj and sniall qnanttties of other excrementitious 
matters, such as lu-ea, the urates, cholestcrine, creatine, and 
creatinine, their proportion being kept down by their con- 
stant removal by the proper eliminating organs. 



CHAPTER IT 



OraOULATIOK OP THE BLOOI>. 



riBCOvory of the circulmion — Physiologicftl (moiojny of Iho heart — ^TaWes of the 
h«aft — MoTemientB of the heart — Impulau at ttic he&rt — ^UMMHloa of more- 
tachta of tlie heart— Force of the heart— Action of llie TtlTB*— Semada gf 
the he*rt^C(ktisefl of ihe soanda of the heart 



Hartet discovered the circulation of tlie Wood in 1616, 
taugbt it in hid public lecturea in 161t*, and in 1628, publislied 
the " Exerciiaiw Anatomica do Mbtu Cordis et Sangxdnia 
in Amtrtdl&>u»y This momentous diacovery, from the iso- 
lated facts bearing upon it which were observed by numer- 
ous anatoinist.9, to ita grand culmination with Harvey, so 
fnlW illustratea the gradual development of most grent phys- 
iological tnithe, that it does not seem out ut" place to be^in 
oar study of the circulation with a rapid sketch of its history. 

The facta bearing upon the circulation, which were de- 
veloped before the time of Harvey, were chiefly anatomteal. 
The writings of Hippocratea ara very indefinite apon all 
points connected with the circulatory system; and no clear 
and positive atatementa are to be foand in ancient worka 
before the time of Ariatotle. The work of Aristotle moat 
quoted by physiologists ia hi& " History of Animals;" atid 
in tliig, oecur3 a passage which aeema to indicate tliat ha 
thonght that air passed from the lunga to the heart; ' but 

I iuBTOTLX, nitkrin dm tnimaiia,far CutaH, Puio, 17S3, lir. L, p. 41 



DISCOVERT OP THE OIRCULATION. 



171 



Id liU woi'k, De PaHi^vs AnlmaUum., it is stated that 
there are two great blood-vessels, the vena cava and acffji, 
arising from the heart, and that the aorta aod itB branches 
carry blood/ Galea, however, demonstrated experiioen- 
tallj tha preasnue of blood in the arteriea, by including a 
portion of one of these vesaela between two ligatures, iu a 
living animal;' but hia ideas of the communication ho- 
tweeu the arterJoa and veins were erroneous, far he believed 
in the existence of email orifices in the eeptnra between the 
ventricles of the heart, a mistake that wiis corrected by 
Tesahuii, about the middle of the sixteenth century.* 

In. 1^53^ Michael Servetas, who is generally regarded as 
the discoverer of the passage of the btood through the lungs, 
or the pubnonary circulation, described in a work on theology 
the courdo of the blood through the lungs, from the right to 
the left eide of tlko beart. Thia description, complete as it 
is, was merely Incidental to the development of a theory with 
regard to the formation of the aonl^ and the development of 
what wer« called animal and vital spirita {spirttus), ^Tho 
game year, at the instiga-tioa of Calviu, Servetua wils burned 
alive at Geneva, and a copy of hia book waa also committed 
to the flames. But one or twocopieiiiof this work are now in 
eiisteuce. One ie in the library of the Int5titute of France, 
and hears evidence, in some pages that are partially burned, 
of the fate which it so narrowly escaped,* 

A few years later, Columbo, professor of anatomy at 
Padua, and Cesalpinua, of Pisa, also described the passage of 
the blood through the hangs, though probably without any 
knowledge of what hsd been written by Servetus. To Cesal- 
pinui ij attributed the first use of the expression, ctrcitlaUon 

> Gb y^dtirii Anwwiiitm, tit., Tenet, 1633, p. 68. 

' Ralbsgb, .-In in Arlerilt Jfialura Satiffuit eamiiMoiw, —Operetf LipsiBa, 
I8i2. vol It., p. ^08, tl *eg, 

• ViaAl.:C9, Offi-i irninia, LiipJ. Batar, 1725, (omiia i,, p. Big. 

* Tlio pliViltjliif^iail portion of the CftriMfMitinni Eeiiitufio of S»^TKrus hna 
been eitruL'lujJ hy Flodbbhh from the original, nnd ia published in hia litlte 
wdrfc eulitli-d., UUloirt tU ia dicotiMrtt tit la <ire»l9tivn du mug, Paria, 185*. 



iT2 



(TTBCULATION 



of the hl4)oi7. He also remarVuLl tliat after ligaturcj or com 
prestiian of veins, the swelling is always below the point of 
obstnictioTi. 

The history of the discovery of the valves in tho veins is 
quite obsftire, thoxigb priority of observation is almost uni- 
versally conceded to FM>rlciu&. As regards this point, we 
can depend only upon the dates of published meraoirsj not- 
withstanding the assertion of Fabricius, that he had i^eeu the 
valves in lii74/ In 1545, fiticnuc described, in branches of 
the portal vein, " valves, which be cfllled aj)opht/se8, and "whieh 
he conipiired to the valves of the heart," * In 1551, Aniatus 
Lueitanus publialied a letter from CannanuSj in which it is 
stated that he had found vfslvea in certain of the veins.' In 
15C3, EuBtachJus published an account of the valves of the 
coronary vein,* In 158G, a clear account, by PiccoUiominoa, 
of the valves of the veius was publisbed.* Fabrkius gave the 
most accumte descriptions and delineations of the valves, and 
hifl first publication is ^aid to have appeared in 1G03.* He de- 
monstrated them to Ilarvey, at Padua ; and it is probable that 
this waa the origin of the first speculations on the mechanism 
of the circulation/ Shortly after the return of Ilarvey &om 
Padua in Hp02, he advanced beyond the study of inanimate 
parts by dissections^ and invcBtigated animated nature by 



' r*miicrrs, jD< Vf^tarum OttiolU. — Opera, Lipe!n>, lflS7, p. IBrt. 

* iiii.SE EuwAKva, ZtfVFM tur !a pAytiQloffif, Pari?, iBGg, mme iit, p. SI. 

* I!en*iLD. Cuwi de pAf/tioioifie, Pariu, 185a, loitie iv.. p. El. 

* EciSTACJlica, De i'etut tiiupari, — Opuifuia^ Vcneiiia, 11163, p. 2ftB. 

' Ptrcoi.itnuisca, Aiiaiomiea Prt^ttHtma, Komre, ISSO, p. 413. The follow. 
ing in the paMiifft rcf^rr«d lo: "rmim soIijid c'h addcM vols, luagoi aitimcntl, 
■b Omnibus pnE>lenDi«aum, quud niilii gunimun ailmJraliuDi'a], quuiu illud com- 
peri, it& cjiC'Jt«TJl, ut ferd in ecsiHsini agereL Qtiod est, in niedua T«iue ntsm- 
ditaa esse innuioernbiliiB peai valvojt, quaiDHdinodiLm in orilicjts rasorum cordb." 

* BEaAKi), tip. ri(., torn*! ir., p, 8S. 

' B^KTtT, £xereiliilii:) Aiiiifomira dt iMu CordU ft San^inU, Frmnpofurtl, 
1428, p. n.^. In our i::'apj of the origmni edilion of ihxt rcmarSciible book, 1$ tb« 
folloHini; munuFcdpt note b; a foniier oviLer : " The vaWt.'a in itiQ hetrt uid 
*da», tlie rnuiauB Dr. Hure^ told tne, gave hini the firet bint of hii granJ dia- 
CO very. — BoTLL^' 



DISCOVEET OF THE CIECrLATION. 



173 



raennsof vivisections As is evident vrlien ive eonEidcr tho 
state of &c;ieQce at that time, anatoioists liad lon^ bee^ii 
pre|>arin^^ the way for the discovery of ilie circululion, though 
tliey knew little of the functions of the parts they deacrilhcd. 
TJie conformation of the heart and vessels, and even the 
aiTaugemei;t of the valves of the veius, did not lead tliem to 
suspect the course of the blood ; but a few well-concoived 
experiments on living animals have made it appear eo sim- 
ple, that we now %vondcr it remained unknown bo long. 
Farthermore, these experimtnta made it evident that there 
Wufl a comraunicBtion at tJie periphery between the iirtei-iea 
Uid the veiQ6, 

lu the Work of Ilurvey are de«cribed, first, tho niove- 
uents of the heart, which he exposed mid studied in living 
animuK He dcscribefi minutely all the plienoniena which 
accompany its action; its diastole, when it ia filled with 
blood, and its systole, when the tibrea of wliich the veutrielea 
sife comjxised contract simultaneously, and *'hy an admirable 
Bdjoatment all the intoraal eurfacw are' dr&wn together, aa 
if with cords, and so is the charge of blo<3J expelled with 
force." From the description of the action of the ventricles, 
he pae.sc% to the aiiriiiles, and eliows liow these, by their con- 
traction, fill the ventricles with blood. By expcnraents 
upon serjx!nt!5 and tiahcs, lie proved that the blood lilk the 
beurt from the vcinB, and is sent out into the arteries, Ex- 
jKieiTig the heart and great vcseck in these animals, be applied 
a ligiiture to the veins, which had the efl'ect of cutting oft' 
the 6U]ip!y from tlie heart so that it became pale and fiaccrid ; 
and by reiuoving the ligature the bloo*l could lie se^n flowing 
into the organ. Wben, on the contrary, a ligature was 
applied to the artery, the heart bctaiue unusuatly disteuded, 
which continued as long as the obi;trnctlon remained. "When 
the ligature was removed, the heart eoon returned to its 
normal conditioiu' 

The descriptiona given by Harvey were the result of nu- 

■ Hxn^xr, UWJa, The Ff dcnliiiiD Society, London, 184V, p. G8. 
12 



174 



CmCDX^TION, 



merous experimeute upon linng animals; cK^tosliig tlie heart 
of cold-blotided animals, in whieli tlie movements are com- 
paratively slow; etuJ^nng also tlie action of this organ in 
warm-blooded aftimats, after itri iimveaicntB liad become 
enfeebled. As we shall see whea we come to dei>cril>e the 
movements of the heart, nothing can eKoecd the einiplicitj 
and accuracy of the descriptions of Ilarvey, which are uoi- 
vcrsally acknowledged to be correct in almoat every pa> 
ticiilar. ^M 

llai'vey completed hie descnptioa of the cireulation, by 
e:ip?rltneute showing the couree of tlte blood in tho arteries 
and veins, and the usw of the valves of the veiiis. These 
experirnenta are models of simplicity and pertinence. Fir&t, 
he allowed that a ligature tightly applied to a limb prc'vented 
the blood from entering the artery and arrested puliation. 
The ligature then relaxed, and applied with moderate tight- 
neaa so as to compreas only the superticial veins, allowed the 
blood to pass into the part by the arteries, but prevented its 
return by the veins, which consequently became excessively 
congested. The ligature being rciiioved, the veiii& soon 
emptied themselves, and the member reg&iued ita or<Iiuaiy 
appetirance.' ■! 

lie observed the "knots" in the veins of the arm when a^ 
ligature is applied, aa for phlebotomy, and showed that the 
Bpace between these knots, which are formed by the valves, 
could be emptied of blood by jireseing toward the heart, imd 
would not till itaelf while the finger was kept at the lower 
extrenriity. It waa imposaible, by pressure with the fingers, 
to force the blood hack through one of the valves.' 

By such simple, yet irresiatibty-coneluaitfe experitnenla, 
was completed the chain of evidence eetablisbing the 
fact of the circulation of the blood. Truly is it &a!d that 
here commeniced an epoch In the study of physiology ; for 
then the Bcientifie world began to emancipate itself from the 
ideas of the ancients, which had held despotic sway fur two 

' op. d/., fi, 65 <tf teg. * Ibid., p. Gfi. 




WERT 



178 



centnries, and study Nature for tLemaelves by means of 
experiments. 

Tlionj^b Harvey deseribed bo perfectly the course of tbo 
blood, and left Dot a sbadow of doubt aa to tbe communica- 
tion between tbe arteries and veins, it wa3 left to others to 
actuallj sea tbe blood in movement and follow it from one 
Bystem of ves&els to the other. In ItJCl, Mnlpigbl saw the 
.blood circulating In the yessels of the hmg of a liTing frog, 
'in examioiag it with maguifyiug glogscs^ and a little luter, 
Lceuwenhoek saw tbe circulatioa in tbe wing of tbe bat. 
Tbe great discovery was then completed. 

Enough has been aaid in tbe preceding historiual sketch 
^to give a general idea of tho eonrae of the great nutritive 
fluid, and the natural anatomical and physiological divisions 
of the circulatory system. There !& a constant flow from tbe 
central organ, to sJl the tissues and organs of tbe body, and a 
constant return of the blood alter It bus pos-sed throngh 
these parts. But before the blood, which has thus been 
brought back, is fit to return again to the system, it must pass 
tbroQgh the lungs and undergo the changes which constitute 
,the process of Eespiration. In some animals, like fishes, tbe 
fttme force sends the blood through tho gilln, and from them 
through the Bystera. In others, like the roptilea, a mixture 
of aerated and non-aerated blood tukes place in the heart, 
and the general ay&tem never receives bluod that ha& been 
fully arterialized. But in man and all warm-blooded ani- 
mals, tbe organism demauds blood that has been fully puriHed 
and osygreuated by its passage through tlie InngSj and liere 
we find tho first great and complete divielona of the circula- 
tion into the pulmonary and systeuiie, or, aa they have been 
called, the lesser and greater cii-culation. The heart in tliis 
instance is double; having a right and left side whiclj are 
entirely distinct fi-om each other. The right heart receives 
the blood as it is brougiit from the system by tho veins, and 
Bends it to the lungs j the left heait receives the blood ti-om 



17C 



OIEOULATlOir. 



the lungB and sends it to tlie BystiemJ It iiiuet be borne in 
mind, Lowerer, that tLougli tlie two sides of the heart tens 
distinct fi'om each other, their action Is simiiltflneoiis ; and in 
studying tbe motions of tbia organ, we shull tind tbat the 
blooti is sent fiimnltnnei>usly trfini the right side to the lung», 
and from the lelt sido tn the ejetein. It will not be neceaeary, 
therefore, to separate the two csircuktionB in our stiid^r of 
their metibaniem ; for the BiitiTiltaneoua action of both sid^ 
of the heart ennbles lis to study its fuiietrona as u single 
oi^u, and the conBtitution and operations of the two ttnda 
of vessels do not present any material differeneea. 

For convenience of stndj^ the circulatory system may be 
divided into Ae-art and vet^h, the latter being of tliree 
kinds: the arteHea, which carry blood from the heart to the 
ayetom; the caj/iUaries, ■which distribnte the blood more or 
less abundantly in difi'erent parts of the system ; and the 
vehiSj, which return the blood from ttie eyetem to the heart. 
The function of each of thtec divisions may be considered 
eeparately. 

Action qf iJie Heart. 
* 
Phi/si dog ical Anatomy of the Heart. — The heart of the 

human subject is a pear-shaped, muscular OT^an, situated 
in the thoracic carity, with its base about in the median 
line, and its apex at tho htlh intercostal space, midway be- 
tween the median line and a perpendicular dropped through 
the left nipple. Its weight is from 8 to 10 ouncea lu the 
female, and from 10 to 13 ounces in the male. It hsis four 
distinct cavities; a right and a left auricle, and a right and 
a left ventricle. Of these, the ■ventricles are the niore capa- 
cious. The heart is held in place, or may be said to be 
attached, by the great vessels, to the posterior wall of the 
thorax, while the apex is free and capable of a eortaln decree 

^ In some anirajtls, a* tlic ilnspng. tlic division betTMii ihc Iwo siilis of the: 
h?iiTt is Ti-ry mjirkcJ. The hi.'ari \9 iFeollj JoliIjIc, hariog two poista, th« ivo 
eldpfl joinvJ k-gecbw ooly at ih« basa 



PTTTSIOUWIOAI. ANATOMY OP THK ffEAICT, 



m 



of motion. Tlie whole organ is enveloped in a fibrous sac 
called the pen'rartlimn, lined by a seroufe membrane which is 
altiH-'lieJ to the great vessels at the base and reflected over its 
surface. This sac is hibricated by a drachra or two of fluid, SO 
thflt the movements are normallj aLcotiiplished withoTit atiy 
fricticin. The eerous pericardinm di>es not present any differ 
erc-es iVom serous membranes iu other situationB. The cav 
itiefi of the heart are lined by a Binooth membrane, called the 
endoeardiuu), which is continiiotia with the lining membrane 
of ibe hlood-vesaels. 

TA/"^ right aurfeh re<¥ive9 the Wood from the reniE cava 
nnd etnptii's it into the ri^ht ventricle, Tbe ftimVle presents 
a prineipal cavity or sinua, as it is called, with a littie appen- 
dix, called, from its reBeniblance to the ear of a dog, the 
auricular appendix. It has two largo openimga for the venn 
cava nHcendena and tbe vena cava de&tiendens, with a small 
opening -for tbe enrouary vein, which brings the blood from 
tho Bubstance of tlie heart itself It Xwia, also, anotlier la.rge 
opening, called t!ie anriculo-vcntrienlar opening, by which 
the blood flows into the ventricle. The walls of this cavity 
are finite tbin as compared witli the ventriclefi, measuring 
aboQt one line. They are constituted of museular fibres 
which are arranged in two layers ; one of which, the external, 
is common to both auricles, and the other, the internal, is 
projier to each. These muscular tibres, though uivoluntary 
in their action, belong to the striped, or what is termed vol- 
untary, variety, and are similar in Btnictnre to the fibree of 
the ventrsclefi. The fibres of the aurieles are much fewer 
than those of the ventricles. Some of them are looped, arieing 
from a cartibiginons ring which separates tbe aiu'ieles and 
veTitricIes, and passing over tbe anrieles; and others are cir- 
cular, surrounding the auricular appendages and tbe openings 
of the veins, extending, also, a short distance along tbe com-so 
of these vessels. One or two valvular folds are found at tbo 
orifice of the coronary vein, jsreventlng a reflux of blood ; but 
there are no valves at tbe orifices of the venie cavaj. 



CIBOFLATIOJr. 

Th^ hft aurkk reeeivea the blood wTiicb comes ttom tie 
lungs hy the pxJuJonarj veius. It tloes not differ materially 
in its anatomy trom the right. It is a little smaller, and its 
walld arc tluclcLT, meosuntig aboist a line nnd a lialf. It lias 
four openings by which it receives the blood from the four pul- 
monary veins. These openings are nut provided with valvea. 
Like the right auricle, it haa a tat^e opening by which the 
blood flows into the left ventricle. The arrangeoieot of tho 
muscular libres is essentially tlie same as in the right auricle. 

In adult life the cavities of the auricles are entirely 
distinct from each other. Before birth they cooimunicate 
by a large opening;, the foramen ovale, and the orilice of 
the inierior vena cava is provided with a membranous fold, 
the Eustachian valve, which serves to direct the blood from 
the lower part of the body through this foramen into the 
left aTiriele. After birth the foramen ovale i& closed, and the 
Eustachian valve gradually disoppeai-s. 

The veTdriclea^iu. the human subject and iuwarm-blood&d 
animals, constitute the bulk of the heart. They have a ca- 
pacity Bomewhat greater than that of the aorieles, and are 
provided with thi'Cik muscular wallB. It is by the powert'nl 
action of thia portion of tlie heart that the blood i& forced, on 
the one hand, to the lun^ra and back to the left side, and on 
the other, through the entire system of the greater cirenlarion 
to the right side. It was supposed by Logallois' that the 
capacity of the right ventricle was conaiderably greater than 
the left, while the more recent observations of Bouillaud' on 
the human heart seem to show that there is no great differ' 
enco between the two sides in thia regard. The most recent 
and conclusive observations on this subject are those of ETif- 
felsheim and Robin.' In these experiments the cavities 
were £lled with on injection of wax, and the estimates 



' Lrulloib, (Eiivm, Psria, I&S4, lome i, p. 831. 

' J, Botut^.4lm^ Traiti Cdniipie dn Maladie* da Ctur, prlffdS it RttlwrrJiim 
nt»tntUttvtrtAnalamitftlaPhiMf>lo^»dti!eUt Otyuii*, Pftri*, 1811,loiueL, p. S4. 
* Journal de tA-naloinU «i lie la Fhjfn6\«^, Pula, juillel, IBM, p. 418. 



]T9 



made bj calcalatmg the amount of liquid displaeeil by the 
tuonlds of the different cavities. Care was taken to moke 
iLe injectioa in animals before cadaveric rigidity set in, ur 
after it bad paeaed away in the hnTnan subject. The coin- 
jiarative results ohtained by these observers are the most 
iaterestino:, for tJie eavities were undoubtedly disteMdecl by 
the injection to their extreme capaeily, and oontainecl more 
than they ever do during life. They found the capacitT of 
the right auricle from ^V to i greater than that of the left. 
The capacity of the right ventricle ivas from -^^ to J greater 
than that of the left, but more frequently there was less dis- 
parity betweeu tho two ventrides than between the auricles. 
The capacity of each ventricle exeseeded that of the corre- 
Bponding anriele by from \ to ^. Nine times ont often, this 
predominanee of the ventricle Tvas more marked on the left 
Bide, The absolute capacity of the left ventricle, according 
to tliese observation B, is from 14-3 to 212 cubic centimeters, 
which is about 4'S to T ounces, Tbia ts much greater than 
most eslimateB, whitsh phiea the capacity of the various cavi- 
ties, moderately distended, at about 2 ounces. The estimates 
of Volkmann and Valentin are about equal to those we have 
cited. 

In spite of the disparity in the estreme capacity of the 
various cavities, the quantity of blootl which enters the cav- 
ities js jiecessfirily equal to that which Is expplleil. This is given 
in the "Cyclopiedia of Anatomy and Physiologry" (vol. ii., 
p. 585) as a little more than two ounces. Tljercare no meana 
of estimating with exaetne&e the quantity of blood dischart;ed 
with each ventricular contraction ; and we find the question 
rather avoided in works on physiology. All -we can say ja, 
that from observation on the heart during its action, it never 
eeems to contain much more than half the quantity in all its 
cavities that it does when liilly distended by injection ; but 
it is the right cavities which are mo&t dilatable, aod prob- 
ably the ordinary qnantity of blood in the left ventricle ia 
within one-fiftb or one-slsth of ita extreme capacity. 



180 



CrKOPLATIOS. 



The ca\'ities of the ventri^'les are trimijjiilar or eonoidal • 
the rigbt Iteing broaJer and shorter tlmu the left, which ex- 
tends to the apex. The inner surface of both cavitiee fe 
mftrked hy pe«uliar ridges and papillse, whioL are calleJ the 
odumnw curne<s. Some of these are mere fleshy rtdgee pro- 
jecting into the cavity ; othens are columns Bttached hy eudi 
extremity and freo at the central portion; and others are 
papLUiB giving origin to the elun-dm tendluew^ wliicln tire at- 
tached in the free edges of the aurieulo-veutriculur valves. 
These fleshy rohimns iutcrlaee in gvcit direction, and give 
the inner surface of the cavities a retit-ulated appearaJico. 
Thifl aiTangement evidently faeilituLes the complete emptying 
of the ventricles during their contruction. 

Tlie walk of the left ventriule are uiiltorudy much thicker 
than the right, Bouillaad found the average thickness of 
the right ventricle at the hase to be 2J lineB. and the tUick- 
ueas of the left ventricle at the corresiwnuliug pai't T lines. 

The an'Hngcmcnt of the nuiscuhir tibrca e«m3titiiting the 
walls of the ventricles is more regular than in the auricle., 
and tlieu- coai-se enables ns to espliun some of the phenom- 
ena which flocompany the heart's action. The direction of 
the fiU'C$ c-anuot be well made ont unless the heart hti.* been 
boiled for a number of houis, when part of the intermus- 
cular tissue is dissolved out, and the fibres can be easily 6e]>- 
arated and followed. Without going into a minute doscrip- 
ilon of their direction, it is suflicient to etnte, in this con- 
nection, that they present two principal layers: a super- 
ficial layer common to hoth ventricles, and a deep layer 
proper to each. The Buperfieial tibiTs pase obliqnely from 
right to left from the base to the ajiex; here thoy take a 
spiral course, become deep, and pass into the interior of the 
organ to form the eohimnse carnt'te. Theae Ghre& envelop 
both ventricles. They may be auid to arise from cartil^lnouB 
rings which surround the aurlculo- ventricular orifices. The 
external aurfiice of the heart is markff.1 hy a httle groove 
which indicated the divlhiou between the two ventricles. 



TALTB9 OV THS UK A 



181 



Fw. 1. 



The deep fibres are circulai', ur transverse, and ^tiiTound 

eacli veutriclc sepanitely. 

Tiie niiiscular tJA^ne of the heart is of a 
deepred color, and resemblos, in its groM 
cLaraetere, tlie fi&sne uf ordinafy voluntary 
museluB; liut, a& already intimated, it jare- 
sents certain peculiarities in its minute niiat- 
omy. The fibres are considerably siujiller 
and more granular than those of urdJaary 
mnscles. They are, moreover, connected with 
each other by short inosculating branchea, 
wliileiii tbevoluntiiryniUBcleeeacih tibwruns 
iroui ite onaia to ita insertion enveloped ja ^ '"'m rmr^i ibeiu- 
ita proper sheath, or sarculeoiina, In the "''"'■) 
heart the tibrea have no sareolenima.' These peculiarities, 
particularly the inosculation of the fibres, favor the contrae- 
tion of the ventricular walls in every direction, and the complete 
eipnision of the contents of the cavities with every systole. 

Each ventricle hflji two oritiecs; one by whitih it receives 
Ibe bloixl from the auricle, and the other by which the bluod 
pusses iiom the rijjht side to the lungs, and from the lell side 
to the syttem. AH of these openings are provided with valves, 
which arc bo arranged as to allow iho blood to paee In but 
one direction. 



Trieuspid Vahu'.^ThU valve is situated at the right 
»«piciilo-venti-i('ular openiiijr. It has tbi-ee curtains, formed 
of a thill but resisting niernbraue, which arc attached around 
the opeuing. The free hordeiu are attached to the chorda 
tcnditicBB, some of ■\vhich arise from the papillfB on the inner 
Burfacc of the ventricle, and others directly trom the walla of 

' Rob™ clatoB (Tratli Ju iTic-roaf^pt. Paris, 1871, p. 670) that the'flbrefl of 
the hL'lirt hsTt^ DO sBTColemmn,, which ia now prttty gcuL-nill)' admiited to ba 
Corfefll, (liougli '&<A\iV.sT(M<U'tuil <tf Microscnpie Anitlumjf,\joni\oQ, 1800, p. 477) 
ways ; " Th^ir sarcoiomrusi is Tery ilelieale, or asia ibaj not be dewotusirilble aA 
milt ucept by tliQ aid of reagi^Qts," 



1S3 



the ventricle Wben the organ is empty, tliese curtsiiiie are 
applied to the walk of tLe vpntriele, lenWiig the auriciUo- 
ventricuJiir opening fvee; bnt wlien tlie ventnV'Ie is l-uui- 
pletely tilled, and tiie tibrea contract, tlieyare forcetl up, their 
free edges become applied to each other, and the openintr 33 
closed. 

P-itlmoni.a Yalvcs. — These valves, also calltfd the ecini- 
luiiar or sigmuid valves of the ri^ht &l(Jo, are situated nt the 
orilice of tlie piilraoiiary artery. They are stroiif; membra- 
noua pijuehes, with tbeir convexities, when closed, looking 
towards the ventricle. They are attached arotind tbe orifice 
of the pulmonary artery, and we applied very nearly to tbe 
walk oJ' the vessel wlien tlie tlood passes in froiii the ven- 
tricle ; but at other times their free edpea meet in the centre, 
forming an effectual barrier to regurgitation. In the centra 
of the free edge of each viilve is a little corpuBcIc called llio 
corpuscle ofAranilus; and just above the margins of attach- 
ment, the artery presents three little dilatations, or Bimisea, 
called the sinuses of Valsaha. The corpuscles of Arantins 
have licen supposed to facilitate the closure of the valves by 
slightly removing' them from the walls of the vessel, so that 
the blood may get behind them. This, however, is probably 
not their function. They aid in the adajrtation of the valves 
to each other, and the eJlectual closure of the orifice. 

Mitral Yaive. — This valve, sometimes called the bicuspid, 
is situated at the Ic'ft anriculo-ventricidnr orifice. It ia called 
mitral from its resemblance, when open, to a bishop's mitre. 
It ie attached to the edges of the opening, and its free borders 
are held in place when closed by the chordie tendioeje of tho 
left s-ide. It presents no material dt'ffereDce from the tri- 
cuspid valve, with the exception that xt is divided into two 
curtains instead of three. 



Aortic Valvaa. — ^These valves, also called the semilunar 



MOViaiEHTS OF THE HEART. 



163 



or sigmoid valvea of the left side, present no difference from 
tbe vslres s.t tlie orifice of tho pulmonarj aiterj". They are 
fritnatetJ at the aortic orifice. 

The physiologiiial anutoiiij of Uie tricuspid and mitral 
Talvea muy be etudied, by cutting away the anricles bo as to 
expose the auriculo-veniricuhir niieningSj lutrotluciug a pipe 
into the pnlnionnry artery and aorta, after destroying the 
seinilimur valvea, and tJien forcing wwler into the ventricles 
by a syringe or from a hydrant. In this way the play of the 
Talres maybe beautifully exhibited. 

We cftti study the action of the eemitunar Talveg, by 
cutting away enough of the ventncles to expose them, and 
forcing water into the veasele. These experiments give an 
idea of the imujenBe strength of the valves; for they can 
hanlly be raptured liy a force which h not fiufBcieut to rup 
tore tlie vessels tbemsel\eB. 



Mcvemente of the Heart. 

In fetudying the phenotneua which accompany the Hction 
of the heoit, we shall follow the course of the blood, bc^in- 
ningwlth it as it flows from the veseels into the auricles. 
Tlie dilatation of the cavities of the heart is calleiithe(A<J«to/-s, 
and their contraction the systole. When these tenna are 
used without any qualification, they are nndei^tood as refer- 
ring to the ventricles ; but tbey are also applied to the action 
of the anriclea, as tbe anricular diastole or systole, which, as 
we shall see, is distinct from the action of the ventriclee. 

A complete revolution, so to apeak, of the heart consists 
in the tilling and emptying of all its cavities, during which 
they experience an alternation of repose and activity. As 
these phenomena occupy, in many wftrm-Llooded aniinnle, a 
period of time le^s than one second, it will be appreciated 
that the most careful study is necessary in order to ascertain 
their exact relations to each other. When the heart is ex- 
posed in a living aniraalj the most prominent phenomenon 



184 



is the altern.ite contraction am] relaxation of tlie veritnL-lea; 
but tbis id oulj (jue of the opemtiionu of tlie organ. In &ny 
of the class of manuiials the auatomj and action of the vaa- 
cular system are to all intents and pur|]ose8 the eame as iu 
the human snhject ; and though the exposure of the heart by 
opening the ehe^t niotlifies somewhat the force and frequency 
of ita pnlsatlons, the various phenomena follow each othear 
in their natural order, and present essentially their normal 
characters. The oj>eration of exposure of the heart may lie 
performod on a living aninjal without any pireat diffifiiltt; 
and if wc sitaply take care to keep up artiiieial re&pu-ation, 
the action of the heart will continue !"or a considerable time.* 
"We may keep the anunal quiet by the administration ot 
ether, or by poisoning with woorara, the latter agent apling 
upon the motor nerves, but having no effect npon the heart. 
Having opened the chest, we see the heart enveloped in ita 
pericardium, regalarly p&rfortnjng its functionis ; and on 
slitting np and removing this covering, the various parts are 
completely exposed. The right ventricle and auride, and 
a portion of the left ventricle, can be seen without disturbing 
the position of the parta; but the greater part of the left 
auriele ia concealed. Aa both aurielea and vontrltrlcs act 
together, the parta of the heart which are exfvosed are suffi- 
cient for purposes of study. 

Action of the Aurk'ks. — Excepting the short time oocn- 
pie^l ill the contraction of the auricles, the&e cavities are con- 
tinually receiving blood on the right side from the system, 
by the venio cavaB, and on the lett eide from^ the lunga, by 
the pulmonary veins. This eontinuea until their cavities are 
completely tilled, tlie blood coming in by a steady current; 
and during the repose of the heart, the blood ia ako flowing 



' For a full dc&cnpdon of ilie opentJDns for «p(V3Li)g the heail in living ani- 
maJs, the render Is fefgrred lo an arlide by ifcje ftutlior ill ibfl Ameriean Jvurnai 
«/ iJu MrJical Scimca^ OcCobcr. IS8I, catitivd ^rpfrimmtal Jietforektl «» potaU 
eQnneek4 vfCMM ArHon of lAe Start and wiA Bef^iratioH. 



UOVEilBNTa OF THE HKABT. 



185 



tlroTigh the patent auriculo-ventricular orifices Inlo the ven- 
tricle^i, Wlien the auriclea hare hecoine I'ully distended, they 
contract quickly and with cunsidemhle power (the auricular 
g^stole), and force the blood into the vcutricles, effecting the 
complete diastole of these caTJties. During tliis contraction, 
the lilood not only ceases, to flow in from the veioa, bnt somo 
of it is regurgitated, as the orifices by which the vessela open 
into the anriolea are not provided with valv&s. The size of 
tbe tturiciilo- ventricular oriticea is one reason why the greater 
portion of the blood is made to pasa into the ventricles; and 
fflrthennore, during the aiiticwUr nystole, the muscular iibrea 
which aa-e arranged around the orifices of the veins constiuct 
them to a certain extent, which tends to diminisli the reflux of 
blood. There can bo no doubt that eouie regurgitation takes 
jilace from the auricles into tlie veins, but tliia prevents the 
possibility of over-disteation of the ventricles. 

It lifts l>een shown by experiments that the systole of the 
anriclea is not immediately nQtessaiy to the perfomiauce of 
the circnlation. M. Marey,' in a reeetit work on tlie clrcu- 
latioti, cites an experiment of Chauveau in which the eou- 
tractiHty of the auricles w_^as teiuporarily exhausted by pro- 
longed irritation ; neverthelesa the veutrielcfi continued to act 
and keep up the circulation. 



Aditm. of the Venfnch'fi. — Immcdifttely following the 
contnicTion of the auricles, wlilcb has the effect of producing 
complete distention of the vetitrjdesj we Imve the contraction 
of the veutricles. Tbia Is the chief active operation peribnned 
by the heai-t, and Ls geuerally spoken of m the Bystolo. Aa 
we should exiject from the gi-cat thickness of the niuseular 
•walla, tho contraction of the vciitriclea is very much more 
powerful than that of the anricles. By their action, the blood 
ia forced from the right side to tbc lungs by tlic pulmonary 
artery, and from the left side to the system hy the tioitn. 
Regurgitation into the auricles is elfcL-tually prevented by the 

MaUT, Circulation At Banff, Paris, ISflS, p. 30. 



183 



OlBCLTUlTroS 



closure of tlie tricuspid and mitral valr«. This act aocom- 
plisln?*], tlie heart lias a period of i-e|)ose, the blood tiovring 
into tlie auricle, and trom them into tlie ventriciles, until tho 
auricles ore filled, and another contraction takes place. 

Locomotim\ of iM Heart — The position of tlie heart after 
death, or duriag the repose of the organ, is with i(s base di- 
rected slightly to the right, and its apes to the left side of 
the body; but with each ventricular Bystole, it raises itself 
up, the apex is rent forward, and moved a little from left to 
right. The movement from leil to right ia a necessairy con- 
sequence of the course of the BUperticial fibres.. The tibres 
on the anterior fiurfaee of the organ are longer than thotiO on 
t!ie posterior eurtace, and pjisd from the base, ivhich is com- 
paratively tised, to the apex, which ia movable. From this 
anatomical arrangement the heart is movtd upward atid 
forward. Their eour&e, (rom the bHv«e to the apex, h from 
right to left ; and as they shorten, the apex is of necessity 
slightly moved from left to right. 

The locomotion of the entire heart forward was observed 
by Harvey in the case of the eon of the Viscount Montgom- 
ery. The young man, aged nhout nineteen years^ snifered a 
Be\-ere injury to the ch&st, rcriuUiug in an abscess, which on 
eicatrijiation left an opening into which Harvey could intrci- 
dnce three fingers and the thumb. This opening was directly 
over the apex of the heart. The action of ll»e portion of the 
heart thus exposed is described by Haxvey iu the following 
words : 

" We also particularly observed the movements of the 
heart, viz.: that in the diastole it was retracted and with- 
drawn ; whilst in the aystole it emerged and protrnded ; 
and the systole of the heart took place at the moment the 
diastole or pntse in the wrist was perceived. To conclude, the 
heart struck the walls of the chest, and became prominent at 
the time it bounded upward and underwent contraction oq 
itself."' 

' H«RTTT. Woria, Liwrf&n. 1817. p. 88*. 



UOYEIIKSTB OF TnE HEAET. 



IS7 



The locomotion of the heart takes place in the tlireetion 
of its asi&, and is due to the sndden distention of the great 
vesseli at ila base. These vessels are eminentlj elastic, and 
as tliey receive the charge of blood fVom the ventricles, be- 
come enlarged in every direction^ and coasei^^ueDtly project 
the entire organ against the wails of the cliest. Tliia 
roovcmeiit is somewhat aided by the recoil of the vontricles 
OB tbey discharge their contents. The diftplacemeni. of the 
bfart dnring its systole haa long been obserx'cd in Tivisec- 
tions, and may be demonstrated in any of the niammala. 
The most interesting observations on this point are those of 
Cbauveau and Faivre, which were made nptfti a monkey. 
In this aDimal, in ivln'ch the position of the heart is very 
much the same aa in the human subject,, the locomotion of 
the organ waa fully establielied.' 

Tmisiing nf the Heart. — Tlie spiral course of the snper- 
ficial fibres would lead us to look for another phenomenon 
accompanying its contraction, namely, twisting, If we 
Httentively wjttcU tlie apes of the boart, eijpecially when its 
action has become a little retarded, tliere is a palpttble twist- 
iug of the point upon itself from lett to right with the syBtoIe, 
Bod an untwisting with the diastole. 



Hardening of the Heart.— It' the heart of a living ani- 
mal be grasped by the baud, it will be observed that at each 
systole it becomes hardened. The fact that it is composed 
aln'.ost exelnsively of fibres resembling very closely those of 
the voluntiiry muscles, explains ibis phenomenon. Like any 
other muetle, during contraction it ia sen&ibly hardened. 

Shorten in ff and Elfrngatwn of the Heart. — ^TEio foi-egoing 
pbenoLuena are admitted by all writers on phygiologj*, and 

' ClunVKjitT KT FAivitE. ^fmrfVm rftherehfa ap^rimtnialM kit Ut mowfmfutt 
Him hr»iu nrirmttux dn cffiur, awitoffia ati feint de cue ih (ti pJtt/tioloj/ir inidicalr, 
IlirK 18B4,p. 24. 



IS8 



CIRCm.ATION', 



COD easily be obscn-ed ; but tUe change in length of the heart 
during its systole has been, aud is now, a matter of distjuaaiun 
All who have studied the heurt in action have ohserved 
changea in length dnnngcontriicttoii and relaxation; but the 
contemporaries of Harvey were divided aa to the |ienod3 in 
the heitrt'a action which are attended with elongation and 
fihortoning, Harvey himself \& not ahstdutely dcdnlte on this 
point. In one passage he e;iy9, in describing the systole, 
" that it ie everywhere contracted, but especially towards tlie 
Bides, BO that it looka narrower, a litil^ It/rtffer, more drawn 
together.'" In his descriptioa of the case of tiio Viscount 
Montgomery, w!io sutTered from ectopia cordis^ he states that 
during the systole, the heart " emerged and protmded." ' Ve- 
Balins, Riolnu, Fontana, and eome otliere, contended tor elon- 
gation during the systole; hut llaller, Steno, LancisJ, and 
Baeauel contended that it shortened. The view generally 
entertained at ihe present day is tliat the heart becoinea 
BhortcT during its systole; but tliece are some eminent ou- 
thoritiea who hold an opjwsite opinion. Among the Intter 
may be mentioned Dra. Fenuocfc and Moore, who made a 
great number of experiments on the action of the hea,rt in 
sheep and young calves. These experimenta were made in 
PbiladL'lphia in 1S39, and it was apparently deirionstratod 
that the heart elongated to such a marked degree, that the 
distance could be measured with a shoemaker's rule. In one 
experitnent (a ewe one year old), ihe elongation was a (jnarter 
of an inch.* Of all the writers of systematic works on phy- 
fiiology, Prof, Dalton is the only one, as far as we know, who 
accepta this view.' The experiments of this observer appa- 



1 HiATOt, D« Molft Cordw, ^., Fruncorartl, 1828, p. S4. 

* HARye*, HVit^. Londuu. IM7. p, 3S4. 

* IltipE, on. iht ifmyt. imenfao Eilitioq by P^ssock, FhiUdclphia, 1844, 

p. BB. 

* D*LTOM, A Treatiat «« ffutnan Phgthloff^. Philndilphift, 1B71, fifth C^tVuc, 
pp, 270,211. The h«wt of tW twl ia mid hy llnHer ta elonRBU iluriug ila 
Tcnlricnlit »;Atol«, tliough tills ifl denied by Foniara (Hh/nrim tie I/alUr, Lan- 




189 

rent])- cunfirui those o("Brs. Pennuck and Moore. Some ex- 
periments made by the aiitlior a few years ago, pulilislied iu 
the " AnieriuHii Juiinial of Medical Sdentrue,'^ Octolier, 1801, 
bad ajtp-ircntiy the same result. There ih no doubt that the 
jKiint t7t' the heart is protruded darinj; the Teutritubir systole, 
as the experiments referred to conclusively prove ; but we 
have been led by the penisal of recent expeninenta by Chau- 
ve«u and Faivre, to recognizG ihe fact that this protrufiiou is 
prubahly dne to other causes flmu the elongatiou of the vcn- 
tricleSj and that during tAe »}jatole tJie ventricUs are ghort- 
^nfd. The ejq^erinient oited hy these euiini$S)t ])hy8ii>l{igists 
ia very simple and coQcluiive. It i& made hy euddenly 
catting the htart out of a warai-blooded animal, and watch- 
ing the phenomena wbieh acuorapany tlie few regular con- 
tractioTis whieli follow. They found tbut the veotriclea 
invariably shortened during the systole. Thia conld easily 
be appreciated by the eye, but more readily if the point 
of the organ Trero brought jtist in contact with a plane 
Btirface at right angles, when at each contraction it k 
anmistakably observed to recede.' This experiuient we 
have Itttely repeated before tlie class of the Bellevuc IIos- 
pital Medical College, and liave eatieticd oiiraeWfs of its 
accuracy. A hirge Newfoundland jnip, about nine months 
old, was poisoned with woorara, artitic-ia] respiration was 
kept up, and ihe licart exposed. A tt or showing the protru 
&ion of (be point and the apparent elonj>ation while in the 



uane, 1190, tome Ui., p. S34) ; but In expcrlmcntbg on the organ utter rictaion, 
Ibe position la nbJcb it U bt'14 ii importauL If, tor c-^dLmple, ve take Lbe heart 
of a iMTtle between tlie thumb and finger aiwi 1iq!i1 Et with the point upiruil, tba 

•cnttido is afl thill aivd flalihy tli4t it *il] bt-coiuo flatitoned iluring thp interi-iiia 
at contractioa, and Ibe pOiiit fill be cObflidcrEbljr olevkLod lit eoch sjstulc; but if 
we TKiecite Ifac pasitioD and bIIdk' the point to huig (tonp, it will tic druwn op and 
the T«(itrid« vili shortan niili tbe JjaLulc 

' OiLicvsAC El Faivjis. «/», ■?'■(., p. U. TheM obaerrcre bIiow tho Bhorlen 
sgaf Uie beati daring its EvetoLcby holcliug it by t^ie gmtt TcBm-bn-lih ihepiHiit 
doinu It Is mate free from Bouruca of error lo ubatrve lUe plitiDouiifiu am tbc 
houi liM on a fiat nurfjce. 



190 



CIBOULATiaBt. 



chest, tlie organ was rapidly removed, placed npon tbe table, 
aad c'oiifiued bj two long m^ecWes passed through the base, 
pmnin^ it to the wooJ. It contracted fur one or two min- 
utes; and at eacsh syatolsj the ventricles were niftiiit'i.'tjtly 
sburtenecl. The ixiint waa then placetl against an upright, 
and it receded with each syBtole about an eighth of an iiicb. 
This phenomenon was apparent to all presents 

In atiothei' expenment, performed a few weelrs later, the 
heart, which liad been esiiosed iu the same way, was exam- 
ined in situ by pinning it with two needles to ft thin board 
passed under the organ. The preaeneu of these needles did 
nut Boeui to iutcrfera with the heart's action, and at eacli 
\'entricular eyatole the point evidently approauheJ tlie base. 
To render this absolutely certain, a knife waa fixed iu tho 
wood at right angles to and toueliiug the point during tbe 
diastole, and a small silver tube was introduiL-od tbrongb the 
walls into tiie left ventricle. At each contraction, a jet of 
blood spurted out through the tube, and thy poiut of the heart 
recetled from the knife about an eighth of uu ineh. The 
animal experimented upon was a dog a little above the rae- 
diitm size. 

Tliese simple experiments demoiietrate that, in the dog 
at least, the ventricles shorten during their systole. The 
arrangCmcjit of the muscular fibres is too nearly identical iu 
the heart of the warm-blooded auiumla to leave room for 
(luubt that It also shortens in the human subject. 

The error wliich has arisen in this reaped, and which 
obtained in our former experiments, h duo to the loeomotioTi 
and pratrusiou of the entire organ, so as to make the point 
strike against the chest. A little rt-fleetion indicat«fi the 
meclianidm of this phonomtriiun. During the intei'vaja of 
contraction, the great vessels, particiikriy tbe aorta aud jml- 
nionarj artery, which attach the buse of the heart to llie poa- 
turiur wall of the thorax, are liLluJ, but not distended, with 
blood ; at each ayslole, however, these veeeela ai-e distended 
to their ntnioBt capacity; their elaatic coata permit of con- 



nMPCLBE OF THE DEAfit. 



191 



aifleriible enlargement^ as can be Been in the living fininial, 
BiiJ tbis enlargfineJit;, taking pkue ia every direction, ptislies 
tbe T-vbule organ forward. AVg have also considerable loco 
motion of tine lieart from recoil. It h for tliU reason tbat, 
observing tlie beart -tn »itt/, tbe ventricles eceni to eknigate, 
land !in inttmment in'pbud ro it apparently indicates removal 
of Uie apex tivtui tlie base. It Is only when we exflmine tbe 
beart tirmly fixed, or eontraotiug after it h removed from the 
"boilyj that ve ean appreciate tlie actual cbnngea whidi occur 
ill the Jeiigfh of the ventricles.' 

In addition to tbeso marked ebangc3 tn form, pf»sition, 
etc,, whicli tJie heart undergoes during its aetiun, wg ubsoi-ve, 
oa careful examination, lbiit the aniface of llie ventricles 
lieuomea marked with eliglit longitudinal ridges during the 
eyfitole. Tbia was not observed by Ilarvoy, but is meu- 
tioued by Ilaller.' 

ImpiU^e of tlie Heart. — Each movement of the heart pro- 
daces a,n impulse, udiicli can be readily ielt and aonietimea 
Been, in the fifth intercostal space, a little to tlie left of the 
mediim line. Vivisections have demonstrated that tlie impulse 
iti syuehronou& with llie cuutrnction of the ventricles. If 
tlie hand be introduced into the dieet of a living animal, and 
the finger placed betrfeen tbo point of tbe heart and the 
walk of the thorax, every time we have a luiixlening of the 
point the finger will be pressed agiiiust the aide. If the im- 
pulse of the beart be feJt while thti lingor is on the jnilsc, it is 
evident that the heart strikes against the thorax at the time of 
the distention of the arterial syatem. The impulse ie due to 
the locom^otiou of the ventricles. In the words of Harvey, 



' TUe oli^erFitions of Foutana on liifl sbgrtviting of tbe heart arc Tcry con- 

ldv& He tiODfitructeJ n litUc iuBirumvat voii^^t^iing of tw-a rerik-ul niliv, alid' 

g an & hdriEiODtal Ijiir like a, shoaa&^a's nii^^iii-c, bne of wbi«Ia n-na upplii^i] to 

the base, uflii tlie othti- just j^niwd tlie apex. He esLimnUtl the sliortiTiini; of tbv 

heart id a iamb at about tKO Pang Imi's {Menu de UaUeTy tome iiL, p. 2^0 J, 

* St«mraia Fhyrioloffiie, vol. i.^ p. 3S6. 



1&3 



OIBGnLATIOX. 



"tlie heart Is erected, and rises upwards to a point, so tliat at 
tilts time it strikes against tlie In-east and ibe pulse h felt ex- 
teraally," ' In the case of the eon of the Yiscount Mont- 
gomery, already reien-ed to, Harvey gives a most graphic de- 
Ecription of the manner in wLich the heart is *' retracted and 
withdrawn" duriug the diastole, and "emerged and protrud- 
ed" during the systole. 

Su0cemon of the Movements of (Re Ileart. — "We have al- 
ready folloTretl, iri a general way, the cooree of the blood 
thi'oiigli the heart, aud the succei?eLve action of the various 
parts; but we have yet to consider these pdiits more in de 
tail, and aecertain if possible the relative periods of activitj- 
and repose in each portion of the organ. 

The great points in the succession of moveraents ore read- 
ily observed in the hearts of cold-blooded animals, where the 
pulsations are very sloiv. In cxaniiuing the lie»rt of thv frog^ 
tiirtkj or alligator^ the alteniatlous of repose and activity ora 
very strongly marked, During the intun,'als of contraction^ 
the ivhole heart i& flaccid, and the ventrlele is couiparat live- 
ly pale; we then see the auriolea slowly filling with Moimj ; 
when ihey have become fully distended, tliey contraut and 
fill the ventricle, which in tliose mximak is single ; the ven- 
tricle irnmeJialely cuutracts, ita action fallowing upon the 
contraction of the auricles as if it were propagated from 
theu], When the heart is filled with blood, it has a dark-red 
color, which contrasts strongly with its appearance after the 
systole. This operation nn\y occupy trom ten to twenty sec- 
onds, giving an abundance of time for observation. Tlie 
case h difterent, however, with the wartn-blootled animals, in 
which the anatomy of the heart ia nearly the same as in man. 
Here a normal revolution may occupy Ic-as than & second, and 
it is evident that the varied phenomena wc have just men- 
tioneil are ftiLloM'e^l with the utmost ditliculty. In 6pite of 
this rapidity of action, it can be seen that a rapid contraction 

' Op. eii. 




8CCCE8SION Oy JIOVEMEKTS or THE DEAIPr, 



193 



of the auriclea precede the ventricular systole, and that tlio 
latter is sjnciiToncma ■witli the impulse. 

Vftrioua estimates have been made of the relative time 
occQpied by the auricular and Tentncnlar contractioRs. This 
intereatior; point has been carefullj studied by ilM. Chau- 
veau and Faivro, by auscultating the heart exposed ia a living 
animal, and establiahing^ by the touch, the reTationa betweeo 
the contraetions of its differyut parts and the heart sounds. 
These observers made a great number of experiment* U]x>n 
horeea and dy^, in which the pulse -vrna not more accelerated 
than the puUe of the human eubject. As the result of these 
obeerrations, the following uiuiiberB are given as representing 
the rhythm of the movements of the heart in man : Aurienlar. 
aystole, C ; Ventrieukr s^i^Btole, 10 ; Diaatole^ S." Though tliis 
estimate is perhaps better than any we had Ijefure^ it is evi- 
dent from the way in -wliieh it was arrived at that it can he 
notliing more than an approximation ; for it Eg impossible to 
estimate accurately, hy the stothnscope and the tuuoh, opera- 
tians wliteh follow each other with Buch rapidity. 

Tiiis que&tion has been at last definitely settled hy the 
late ohservatione of Marey, who has coimtnieted Bome very 
ingeuioUB inBtrument& for registering the form and frequency 
of the pulBe. He deviaed a Beries of most interesting experi- 
ments, in wliicli he was enabled to register eimidtatieously 
thti pulsatione of the dlt^LTt-nt divisions of the heart, and has 
succeeded iu establiehing a definite relation between the con- 
tractions of the auricles aud ventricles, Tlie method of M. 
Marcy enables us to detennine, to a Bniall fraction of a sec- 
ond, the duration of tlie contraction of each of the diviaiona 
of the heari. 

The method of transmitting the movement from the heart 
to a registering ajiparatus is very simple. It coneists of two 
little elastic hags connected together by an elastic tube, the 
whole clused aud hilud with air. A pressure, like the pres- 

' CbaUtuv n Fiii-HE, ap, eit,, p. 18. TheM aulliora r«]irv?(<i;t tlw rLytha 
bjr iDuainl cotes, which bave hwtt t«du™ii to the aumbers gluen nbove. 



194 



UUtOL) L JLTIOIT. 



Bure of the fingers, upon one of these bage producea, of coarse, 
an instantaneous and corresponding dUatation of the other. If 
■we suppose one of three liagw to be introduced into one of the 
cavities of the heart, and the other placed under a stuaU le- 
ver, 9o arranged on r pivot as to be sensible to tlie slightest 
impression, it ie evideat that any compression of the hag iu 
the heart would produce a corresponding: change in vuhime 
in tlis other, which wmiUl be indicated by a niuvement of 
the leYer. M. Marej baa arranjf^'ed tlie lever with itii Bbort 
arm on the elastic bag, and the long ann, provided with u 
pen, moving against a roll of paper which pasj^es along at a 
uniform rate. Wlien the Jever is at retit and the paper &et 
in motion, the pen will make a horizontal mark; but when 
the lever ascends and descends, a corresponding trace will be 
made, and the duration of any mos-euient can readily be es- 
timated liy calculating the rapidity of the motion of the 
paper. The bag which receives tJie impreesion is callml by 
Marey the initial bag, and the other, wiiich is connected with 
the lever, is called the t^miiiml bag. The former may be 
moditier! in form with reference to the Bituation in which it 
is to he placed. 

The e.vperimenta of M. Marey, with reference to the rel*- 
tions between the eystole of the auricles, the systole of the 
ventricles, and the impulse of the heart, were perfonned upon 
hoi'ses in the following way: 

A Bound ia introduced into the ^ght eide of the heart 
through the jugular vein, an operation which is perffirined 
with certainty and ease." This, sound is ]iro\ided with two 
initial bags, one of which ia lodged in the riglit auricle, whik 



' Cathctori^stioB of the «avit)ee of the hmri, cMpcrially upon Ihe right ajde, U 

an apenitioiiriuiiiliiirlo phyniiologiaU. Willi n donbW t^DUlo, pucIi m is described 
bj U&re; (p. €1), of die Tcqiuuite dimcufiione nud witb the proper oureB, it mim 
be oaay to lod^e 11)* bags rcsppclivelj in the aaricle and Toniriule; tfpKiiH; in 
D3X BJiimal of large aiie like Ihe liorso. A lulie i* easily hitrodiiocd Snlo the ri(?lit 
aide of tlie Iicitrt, ia tlio dog, tlirough llie eiUiTial jugular. M. Matejf gi»« full 
delAlla of event step, of the oporation, and ilLere caa be Do dottbtof the fiicililTkDd 
aciuiuej irilU whicU it m»j bw [lurfoimed. 



SUCCEHdIOH 



rEMESTS 07 THE HEART. 



105 



tli'n oilier piis9ea into the ventriiHe. The bags aro conaecteJ 
with distinct tubes which paes one withiu the other^ and arc 
connected by ehistic tmliing wilh tlie regiateriiig Eipparutua. 
At each ajstole of the heart the b^s in its caviticsa are coTn- 
presaed, and proclnce corresponding movemeats of the levers, 
which may be rpgistered simultaneously. 

To register the inqmlse of the heiM% mi indsion is made 
over the point where the apes-beat is felt, throngh the fikin 



Tta. L 



AE 



-^^ 



Hfc-nrtt mprertnilrtE Hie ■"MfrfiBurojiVf " of Murey. ""nic InFtmineiit Ii coKifio**! 
i)i lum prtuctiinl sLpitiibtiIi' : A E, IIip r'^fiffiriitd ap/iarafut. iiiiil A S, tho gpkfigin^- 
gf^Me ofjaiviii*, t\iK 1" to ftij. nlkU'!^ Ti!7<:lr?i«, Inin^mlK nnil ufDiiUfli'p Ctaft 
■DDVanif'ati wt>kh Hre lu be ttU'tieil." Thi' r>inapri'»itili>i> cuTti.')! upun *}i« b^ e. 
Which U plBced uvei the ■pnS'ortLc huan. bt'iwvcu iliv fciutrc'iwiiil uium-lci', tti ron- 
dnciuit by ihe lub« t e, Hhfcli 1» Hlkvl nilU nlc. kj ihi' flrs< kvor. Tli« i:i>[uiire»ii![on 
exun«(l u]i(i'n tbe ba^ o ■□<! t>, in lav doutk H-onii, i» ciin'luetE'd by ili^ tci'^i-n (o 
■Dd III Ui ilw two remaLiiJiiLj lc:»i;t». Tht- cuTcnitaJa cf llie Itveri are rcjnBlcreil 
■liDoltaowailT bT tlie cylinders AlL (ILuuT, flur ^ta clrouAtltvn (ia tana, purlB. 

i8as,p.u.) 



ftiicl external intercostal muscle. A little bag, stretched over 
two metallic bntloud separated by a central rod, ia then care- 
fully secured in the cavity thiia formed, and connected by an 



196 



OIHCUIJkTIOIT. 



elftstio tiibe witli the regiatermg ftppnratiis. All the tubes 
are provided with stop-eocts, so that each initial bfig may be 
made tv communicate with its lever at will. "Wlien the oper- 
ation is conclutleJ, and the souud firmly secured in place hy 
a ligature around the vein, the animal e.\['erieuce6 no incon- 
venience, is able to walk fihout, eat^ ifccj and there is every 
evidence that the circulation is not inteiicred with. The 
cylinders which ciu-ry the pajier destined to receive the traces 
are arranged to move hy cluck-work at a given rate. The 
paper may aUo l>e ruled in lines, the distance* between which 
represent certain fractions of a &et:ond. 

Fij5. 2. taken from the work of Marey, represents the 
apparatus reduced to one-sixth of ita actual size. Two of 
the levcra arc connected with thip douldc sound lor the riglit 
anriele and ventride, and one ia connected witJi the hug des- 
tined to receive the impulse of the heart. 

In an experiment npon a horse, every thing- being care- 
fully arranged in the way indicatedj the clock-work was set 
in motion, and the movenienta of the three levers produced 
tracefi upon the paper which were interpreted aa follows : 

1. The paper was ruled &o that t-atli dtvibion represented 
one-tenth of a second. The traces formed hy the three levers 
indicated l'«iur revolutions of the heart. Tlie first revolution 
oc;cu[)ied 1^ sec, the second 1^ aee., the third 1-^ sec., and 
the tbni'th 1 sec 

2. The auricuh'ir eystole, as marked hy the firfet lever, 
immediately precedwl the ventricular wystole, and occupied 
ahoiif- t.wo-teTitha of a s&:(nid. The elevation of tlie lever 
indicated that it was much more feeble than the ventricular 
gyatole, and Buddeu in it.s character; the contraction, when 
it had arrived at the maximum, being immediately fol- 
lowed by relaxation, 

iJ. The ventricular systole, as marked by the &ecoud lever, 
followeil ioimediately the auricular systole, and occupied 
ahaut /our-tent/is of' a secortd. The almost vertical direc- 
tion of the trace, and the degree of elevation, showed thnt tt 




rOECE OF THE HKAHT. 



197 



Buddon and powerful in its eliaracter. The abrupt de- 
"seenl f>f the lover showed tliat tbe relaxation was aiiiittdt iu- 
stai3taii<?ijti8. 

4. The iiiipiiliie of the heart, as markeil hy the third lever^ 
■Kss shown to be abeolutelj Byuclironous witii the ventrituhir 

BVBtolo.^ 

Coudensing the general results obtaioed by Ifarey, which 
are of course subject to a certain ainoant of vanatior, we 
have^ dividing the action of the heart into tea equal parta, 
three disTinct periods, whi«h occur in the following order ; 

Auricular iS^y^/o^— This occupies two- tenths of the heart's 
action. It is feeble compared M*itli the ventricular systole, 
and relaxation iiiinifdiately lulluwa the contraction. 

YeniriGtUar Sy^Ude. — This occupies four-tentba of the 
lieart's action. The contraction ia powerful, and the relaxa- 
tion sudden. It ia absolutely sj'uchronoua with the impulse 
of the heart. 

J}i€(M<M, — This occupies fouMenths of the hearths action. 

Fwm of the RmvL — There aio few points in physiologj' 
on which o])inions have been more widely divergent, tliau on 
the question of the forw! employed by the heart at eacii con- 
traction. Borelli, who was the first to give a definite esti- 
mate of this lorce, put it at 160,W0 pounds ; while the calcu- 
lations of Keill give only 5 ounces.' These e&timatea, how- 
ever, were made on purely theoretical grounds. Borelli esti- 
mated the force employed by the deltoid in siietaining a given 
weight held at arufs length, and Ibrnied hie estimate of th@ 

" Haikt, op. fit., p. 63 ft tutq. I liftvi! prtferred (o give the genoral algnill- 
Gtoce ol iht lhn.-e tracts ulitnini^:! bv Mjiicv, cut^HT clina reprtxiuee the trnccft 
tlj«uBi-Is.?B, wliiL'Ii preiimn cerwio minor cliataLiypa w1»ith miglit tgiifuse the wnii- 
vr. NoUiing coulii be more duitiuct thim i1ie illiiBtrntion of til's pnnJt-ukr points 
■bore cuurntniioiJ ; aad there can be no othiT ojiinion iUil[i tlidt the^i; obstirTa- 
tiiHU fclllc the tjucHtion or ihu rbjthio of tht hi^iu-t's &i::iioti in the tui'uaith no 
trbicli the CVfHriiniLTilfl n'lTP ptrfuraied. 

■ Jauxs E^ill, H.D., £m(1^ on Sneral Farli of tht Animal <Economg, Lon. 
lion, 1717, pp. 87, Ul. 



198 



CTECrLATlOJf, 



power of tlie lieart by cctiipariTig the weiglit of the or^n 
with tliat of tbe delttiirl. Koill made liia estimate from a 
cuk-inlution oP tbe rapidity of the current of blood in tlie 
arteries. Hale^ was tbo iii^t to investigate the <)uestion ex 
peri men tally, by tlio application of the cardiometer. H© 
6lior\-ed that the presaurc of IiKkm] in the aorta could be racsis- 
ured by the hc-ight to whic-h the fluid wvuld rise in a tnlje 
Connected with fhnt vessel, and estlraated the force of the 
left ventricle by muUiplyin*,' the pressure in the aorta by the 
area of the internal surface t»f the ventriele. Tlie cardionioter 
has undergunc vartouB improTemente and luodifl cations, bnt 
this is tlie prineijile which is so extensively made use of at 
the present day, in estimating the pressnre uf the blood in 
diftefent parti of the tirculatitry system. First we have the 
improvement of Poij^euille, who subfttitnted & U ttibe partly 
filled with inerciiry, for the ]ong stTaight tube of Hal w; and 
tlien the various forms of eiirdionieters constnicted by JVIagen- 
die, Bernard, JIarey, and others, which will be more fully 
diBcns6ei] in eonnectiun with the arterial circulation. These 
inatinimeuJs liave been made ijse of by Marey, with %'ery 
good ref^ults, in invest] g:ating the relative force exerted bj" 
the dift'erent divisions of the heart. 

Halca estimates, from experiments npon living animals, 
the ht!ij,'^ht to which the blood would rise in a tube conneetej 
with the aorta of the human subject, at 7 feet 6 inches, and 
gives the area of the lelt ventricle as 15 square inehea. J^rom 
tlila he* etiiimate^ the force (ff tlie f-eft ventricle at 51'5 pounds.' 

Thiiugb this estimate is only an ap]iro.^imation, it eeems 
bftsc'd on more rcasonuble data than any other. 

The a]>paratn5 of Miirey for regifitering' the contrac- 
tions of the ditt'erent eavittes of the heart enabled him to as- 
certain, hUo, the comparative force of the two ventricles and 
the rij^ht auricle; the situation of the left auricle as yet pre- 
cluding the possibility of iutrodiit-ing a sonnd into ite cavity. 

'' STKPnKN Hales, B.D.,F.R.S„jrc.,<SlWiMi/£«[>y«.- Coniiuninff nmntaiialivtii, 
ftA, London, 118». VqL IL, p. 441. 



ACnON OF THE VALVES. 



199 



Bj first Bubjectin<» the hngs to known degreee of pressure, 
Hie degree of oIevfitiii>n of a lover nmy be graduated bo m to 
repre&ent tlie degrees of the cnnlioiiieter. In analj'zing traces 
made by tlie left ventricle, rtf^bt ventricle, and right atu'icle, 
in the hon*p, ]\rarej found tlin.t, as a gciieifll nilo, the 
coinjiiinitive (brceof tlie right and li'll ventricles i& ns 1 to 3.' 
The force of the right auricle ia compumtively ineignifi- 
cant, lining in one case, as MBipareJ with tlie right ventricle, 
only as 1 to 10. 

Action of the TWfVj*,— We have already indicated the 
coarse of (he liluud through the tavlties of the heart, and it 
\xm Well appRrent that the tiet-essjitlKs of the cireuktion de- 
mand some arrangement hy -which the current shall always 
l>e in one diret-tiini. The anatomy nf the valves which gnard 
the orifices of the ventricles gives an idea of tlieir function ; Imt 
•we have yet to consider the precise mechauiBm by which they 
are opened and clo&ed, and the way in whitJi- regurgitation is 
prevented. 

In man and the warm-blooded animals, there are no 
valves at the titiiices l)y wliich the veins open into the atm- 
cles. As has already been seen, compared Tiith the ventri- 
cles, the furco of tlie aurieles ia tostgnifieaut; and it has 
farthorinoTO been Bhowii by espcrimeiit that tlie ventrictoa 
may be tilled i^ith bluod, and the circnlation continue, when 
the auricles are entirely paasive. Though their ontitie.s are 
Dot provided with valves^ the circular aiTangeinent of the 
tibn.'S about the veins ia snih, that during the contraction 
of the auricles tlie opetiinga are materially narrowed, and re- 
gurgitation cannot take place to any great extent. Tho force 
of the blood flowing into tlie auricles likewise offers an obsta- 
cle to its return. There is really no ralvular appiiratua which 
oporatcs to prevent regurgitation from the heart into the 
veius; for the valvular tbUs which are so nuineron& in the 



* Uauy, <^. oV., p. 1!>4. 



aoo 



CUiCCLATlON. 



geuenil veiions system, anri particularly in tlie vem9 of tbo 
extremities, du not exist in the veiioe cavte. 

The eoutinuoiis flow of biooU from the veiDB into tha 
auricles, tlie feeble character of their coutraetlons, Ihe ar- 
rangement of the fibres amund the oi'ificen of tho vesseU, and 
the great size of the aiiriculo ventricular oiteuiiigSj are coridi- 
tiona whieh provide sufficientty well for tho flow of blood luto 
the ventricles. 



Aurivulo -Yentriculftr Vuk-e^. — After the vetitrides have 
become completely distended by the ani'icular ey^tule, they 
tftke on their Gontniction ; whieh, itivilt be ivraembered, is 
very many times more powerful than the contraction of the 
auricles. They have to force open the valves whicli close the 
Ofifices of the pulmonary artery and aorta, and empty their 
contents into these vessels. To accomplish this, at the moment 
of the ventricular systole, there is an instantaneous and com- 
plete closure of the auricnlo-ventricular valves, leaving but 
one opening through whieli the blood can pass. That tbese 
valves close at the mouient of contraction i}f the veiitriclea is 
demoiistrated by the experiments of Chauveau and Faivre, 
who introduced the finger through an opening into the atiri- 
cle, and actually felt the valvea close at the iiietaiit of the ven- 
tricular eystole.' 

This tactile demonstration, and the fact that the first 
Bound of tlie heart, whirh is produced in great part by the 
closure of the an riculo- ventricular valves, is absolutely syn- 
chronous with the vetjtricnhir sy&tote, leave no doubt as to 
the medhaiiiara of the closure of these valves. 

It h probable that na the blood flows into tho ventricles 
the valves are slightly floated out, but they are not closed un- 
til the ventricles contract, A Oerman ])hysiologifit, Bnum- 
garteii/ has attempted to show that the valves are closed by 
the contraction of the auricles, ba^^ing thi& opinion upon the 
fact that M'hen tho auricles are cut away, and flaid is poured 

* Cp. rii., p. 21 * UitnK-KpwAtu^ op. dt., tomo iv,, p. 31. 



ACnON OF THE TALTB8. 



201 



tlimiigli tlic aHrifulo-ventricular openhij;, tlie valrcs are 
floated up, and iinall j eloseJ TPhen tbe ventricle h cotnpJetelj 
filled. Thia experiment we have repeated and fotinJ to 'be 
correct; Itut in tliis way we are far Jtopi fulliniiig the natu- 
rftl cotiditioDS of the circulation. In tiio natural nctiou of tlio 
heart, the hlood flows from the auricles in n large streain^ 
"whiuh opens the valves and applies thein to the walla of the 
ventriclep. TJiis is quite diti'ereut froni the action of a einall 
Btreani, which may ingiimate itself Itetween the lip& of the 
valves, anJ force them up by reacting from the veutricle. If 
the serailanar valves he expneecl, and the artery closed, a 
Stream of water poured from the ventrielca vnW close the 
valves; ami jet we could haixlly say that in the natural course 
of the circulation the valve:!, at the artei-ial oriticee ai*e closed 
by the veiitrieular systole. 

These experimotits do not throw any doubt upon the fact 
that the aurieulo-ventrieiilar Vidvee. are closed by the pressure 
of blood against them duriuf^ the veutrjieular systole. 

If a hulloek's heart he jvrepared liy cutting away the auri- 
cles &o as to exp<.«e the luitral and tricuspid valves, securing 
the nozzlea of a double syringe in the pulmonary artery and 
aorta, after having destroyed the seinilunar valves, and if 
fluid l»e iujeetod simultaneously into both ventricles, the piny 
uf the valves will he esliibiterl. The mitral valve effectually 
prevents the passage of the fluid, its edge& being po accurately 
appro xi united that not a drop passes between them ; hut when 
tlie pressure is considerahle, a certain quantity of fluid passes 
tlie tricuspid valve. There ie, indeed, a certain amount of 
insufficiency at the right auriculo-ventrieular orilice, wbicli 
does not exist on tlie ujiposite aide. 

Tliis fact was first pointed out by Mr. T. "W, Xing,' and is 
called by !iim the ^'' safety-valve function of the n't/A/ r«j- 
tHcU." The advantage of this slight insufficiency is apparent 
on a little reflection. The right ventricle sends its blood to the 

' Krnn, An Eaa\f on thu Safety-valM Pundi&nt of the RigM Ventrirlt of thr 
fftmitn lleart.—Ou^'t HntpUal lifporb, 1837, vol. !i.. p. 104, 



203 



CiRCCLAHOH. 



lungs, where, in order to tWiilitale the respiratory processes, 
the VTfllls of the capillariea are very tliiu. Ttie lungs tliem- 
*elv69 are exoeoJiugly delicate, and an effusioTi uf blond, or 
eoitaitleralile congestion, would be liaUIe to be folluw&l by 
&erious conaequeiices. To prevent tliia, the right ventricle h 
not jiermitted to exert all its force, imder oil circiiniBtances, 
npou the blood goin}^ into the palinoiiary artery j bat wUeu 
the action of the Iieart is exaggerated tipom any cause, the 
luii^ are relieved by & sHj^'ht regurgitation, which taices 
pbifie through the trieuspid valve. The lungg are still farther 
protected by the sutfieieiicy of the mitral valve, which pro- 
viclea that no regurgitation shall take phiee into their substance 
from the lefb licurt. In the aystemits eircubition the capilla- 
riea are less delicate ; extrava^tlon of hlgod would not be 
followed by any serious results, and the eircuhiling fluid 13 
made to pass through a considerable extent of the elat^tic 
vespcls, before it bcgiua to be distributed in the tissues. It h 
evident that un the lelt eiile thertj is no ueceasity for eueh a 
provision, and it does not exist. 



A&rtio and Pulinnnic VaUea. — The action of tho semi- 
lutmr valves is nearly the same upon both sides. In the in- 
tervftU nf the ventricular contractions, they are clc>^ed, aud 
prevent regurgitation of bluod into the veniriel^. The sj:*- 
tole, however, overeoinea the reaiatance of these valvra, and 
forces the contents of the ventrieled into the arterie^i. During 
this time the valvea are applied, or nearly appUcd, to the 
walls of the veasel ; but as &oon ad the ventricles tease their 
eontraotion, the constant pressure of the b]<WH"], which, as we 
shall see hereafler, is very great, inutantatieouely eloses the 
Dpeningfi, 

The action of the eemiluuar valves can be seen hv cutting 
away a jwrtiou of the ventricles in the heart of a large ani' 
lual, eecuring the nozzles of a double &}Tinge in the aoi-ta and 
pulnionaiy artery, and forcing water into the ve3se]8. la 
performing this experiment, it will he noticed that while the 



gOCNDS OF rOE HT5ART. 



203 



flortic semilunar TJilves oppose the passage of tlie liquid so 
effeHaall^ that the aorta mny be niptiiriod before the valves 
will give way, a considerable (le^-ee ot' id sufficiency esi?td, 
iimler a Iiijiih pre^iircj at the oriiiee of the pulmonary artery. 
There is at this oriticc a safety-valve tunctiou m important 
as tlmt ascribed by Kini^ to ttie tricuspid ralre. It i? evi- 
dent that the slight inautficiency at the piilmoniic orifice may 
be eveji more directly ini^wrtanit in protecting the iunga than 
the insiifRcienoy of the tricuspid valve. T!ie difference iu 
the sufficiency of the semilunar valves on the two sides is 
fully as marked as betiveen the auncrulo-ventricnlar valves, 
and it is surprising that since the oliservations of King, this 
fiict has not attracted the attention of pliyBiologistft.' 

It is pi'oUubIc that the eorpuseles of Arantiua, ivliich 
are situated in the midillc of each vitlvula!" curtain, assist in 
tliei accurate closure of the orifice. The sinuses of Valsalva, 
situated in the artery behiiid the valves, nre regarded as facil- 
itating the closure of the vslves by alluwiug the lilooU to pass 
easily behind tliem. 

Sounds of the HcarL — If the ear be applieil to the prje- 
cordial region, it will be foniid thiit the uetion of the heart is 
aceoiiipauied.by certain aoundfl, A cai'oftil study of tliese 
eomula, and their inndifieations in diAeaee, has enabled the 
practical physician to distinguish, to a certain ei^ent, the 
conditions of the heart. ThU increapses the purely physiologi- 
ciil intei'Cdt wiiich attaches to the audible inanifestatiotis. of 
the action of the fjreat central organ of the circulation. 

The appreeliible phenomena which attend the Iieart'a 
action are'cuiinecte«l with the ayatole uf the ventricles. It is 
this which pro<lucea the impulae aj!;ainst the walla of the 
thorax, and, as we shall see fartlier uii, the dilatiition of the 
arterial systeni, called the pulse. It is natural^ therefore, in 



' Ttik olistrvaUon vit.i first mn^Iti, miil the fru:t publicly dEmoDatrntcil, In 
the coiiTM OQ pbj^iiiolugy ikt the Dcllcruc Uuapital Xuilicul CoUcge^ afis-slon of 
180(-'06. 



204 CIBCULATION. 

stndying tliese phenomena, to take the Bjstole as a point of 
departure, instead of the action of the auricles, which we 
cannot appreciate without vivisectiona ; and the Bounds, 
which are two in number, have been called first and second^ 
with reference to the systole. 

The first sound is absolutely synchronous with the apex 
beat. The second sound follows the first without any appre- 
ciable interval. Between the second and first sounds there 
is an interval of silence. 

Some writers have attempted to represent the sounds of 
the heart, and their relations to each other, by certain sylla- 
bles, as, " luhh-duj) or lubihtub ;" ' but it seems unnecessary to 
attempt to make a comparison, which can only be appre- 
ciated by one who is practically acquainted with the heart- 
sounds, when the sounds themselves can be so easily studied. 

Both sounds are generally heard with distinctne^ over 
any part of the prsecordia. The first sound is heard with its 
maximum of intensity over the body of the heart, a little 
below and within the nipple, between the fourth and fifth 
ribs, and is propagated with greatest facility downward, 
toward the apes. The second sound is heard with its max- 
imum of intensity at the base of the heart, between the nipple 
and the sternum, about the locality of the third rib, and is 
propagated upward, along the course of the great vessels. 

The rhythm of the sounds bears a certain relation to the 
rhythm of the heart's action, which we have already dis- 
cussed ; the difierence being, that we hero r^ard the heart's 
action as commencing with the systole of the ventricles, while 
in following the action of different parts of the organ, we 
followed the course of the blood, and commenced with the 
systole of the auricles. Laennec, the father of auscultation, 
was the first to direct special attention to the rhythm of these 
sounds, though they had been recognized by Harvey, who 
compared them to the sounds made by the passage of fluids 

' C. J. B. WiLLlAHa, in DimglisoQ'a Human PhytuAoffj). FbiUdelpbia, 1856, 
ToL i., p. 898. 



BOCKDS OF THE Bf-ART, 



205 



along the oesoiihngus of a horse when drinkinjr.' He ilividea 
n single revolution of the heart into tour parts: the first two 
jiarts are occupied by the first sound ; the third part hj the 
second 9otind ; and in tho fourth part there is tio sound.' 
He regards the sei-ond sound a8 following- imTnL>diatelj after 
the liret. Some authors btive described a " short $ileticc" «a 
occiiTrinf;^ after the first sound, and a "long BHeuue" after 
the second. The eliort Hlenoe, if appredablc at all, is so 
indistinct that it may i»nu!liirally be disK-garded. 

Attempts have been made to improve npon rfiis diviaion 
of Laenuec, l>y dividioj; the heart's action into three eipial 
partB, as is done by M. Beau;' the first being occupied by 
the first sound, the second by theseruud sound, and the third, 
eileuce. This hardly needs diufussion. M. Beau bases this 
division u|>on ii theory of tlio production of the aounda which, 
though pretty generally diseussed hy phy&iologiate, ib, m far 
as we have &een, adopted by none, and ia bo entirely op[itipcd 
to facts that it hardiy deiimnd» coinnient. It h evident to 
any one who haa heard the sounds of the heart, that the first 
h longer thnn the eet-ond. 

M<->st phjsiologislB regard the duration of the first sound 
as a little less tlian two-fonrthg of the heart's action, snd the 
eecond &onnd an a little more than one-fourth. Whun we 
come to consider the mechanism of the production of the two 
Boiimls, we fihnll eec that, if our views on that point be correct, 
t/i^ Jfrsi scum/ ahovld fin'^vjitf the perloil of the ventritntlar 
gysto!'\ or foitr-UuUha of the hearths action, the secnnd sound 
(tlo'tt thrt^-Umtha, and t/i^ rfpoae tkr^M^ntfii. 

The firtt sound is relatively didl, low in pitch, and made 
up of two elements; one, a valvular element, in whieh It 
re?emljlee in character tfie feeond sound; the other, sin ele- 
ment which is due to the action of the heart aa a muacle. 
U baa been ascertained that cill muscular contraction id nt^ 



• Op. cit., p. 32. 

* Ljtt-KXiu-, Train de C AtuaiUaium Miiiiate, Piri*, 1S8T, tome ui., ■p. 48, 

■ Duv, J^aite apirimmtaU et tiiitiqiu d'AimcuHalioa, FarU, li58, p, 528, 

H 



CIEOULATION. - 

tended with a certain Bound. To this is added an impnlsion 
element, which is produced by the striking of the lieart against 
the walls of the thorax. 

The second sound is relatively sharp, high in pitch, and 
has but one clear, element, which we have already alluded to 
as valvular. 

Cause of the Sounds of the Heart. — There is now 
scarcely any difference of opinion respecting the cause (rf the 
second sound of the heart. The experiments of Rouanet, 
published in 1832, settled beyond a doubt that it was due to 
a closure of the aortic and pulmonary semilunar valves. In 
his essay upon this subject, Rouanet acknowledges his indebt- 
edness, for tlie first suggestion of this explanation, to Mr 
Carswell, wKo was at that time prosecuting his studies in 
Paris.' 

The experiments by which this is demonstrated are aa 
simple as they are conclusive. First we have the experi- 
ments of Rouanet, who imitated the second sound by produ- 
cing sudden closure of the aortic valves by a column of water. 
We then have tlie experiments, even more conclusive, of the 
British Commission, in which the semilunar valves were 
caught up by curved hooks introduced through the vessels 
of a living animal, the ass, with the result of abolishing the 
second sound, and substituting for it a liissing murmur. 
When the instruments were withdrawn, and the valves per- 
mitted to resume their action, the normal sound returned.' 

It is unnecessary to discuss the Tarious theories which 
have been advanced to explain the second sound, as it is now 
generally acknowledged to he due to the sudden closure of the 

' Cyclopadia of Analomg and Phymologg, vol. il,, p, B17, In tbie nrtJcle, we 
find I)r. Elliott, of Carlisle, nlluded to as h&ving stated in his the^ published in 
1S31, " that the second sound of the heart is dependent upon the nub of blood 
from the auricles into the ventricles during their diastole, and also upon the sud- 
den flapiiing inward of the aigmoid valves at the origin of the large arteries by the 
refluent blood." 

Mbid,p.«18. 



CATTSE OF THE SOlTSDfl OF THH tt kAb t, 



207 



temtlunar va-luen at i/tc oryftws of the aorta iijtd ptihnonartj 
artery. Wo retuark, liowerer, that the fiound is bciini with 
ita maxinmin of intensity uver tin; eite of tlieae valves, and is 
projiftgnted alung the great vessels, to which they are attfLch- 
6(1. It akii OL-cnrs prctiAely at the time ot'thciL' cloBlXfe; L e., 
immedinte]y fuUowitig the ventricalar tyetole. 

The cause of the lirat sound of the heart has not, until 
■ffithiii a few years, been as well underetood. It wns maintain- 
ed by liouanetj that this sound was produced by tho sudden 
closure of the auriculo-veutricular valves; hut the situation 
of thc^e valves rendered it diffioult to denioustrate this by 
actual est>eriment. We have already seen, that while tlm 
second sound is purely valvular in its charttcter, the first 
Sound is composed i^f a certain numherof diflcrpnt ylenients ; 
but auscultatory e^xperimenla ba>'e been made by which all 
but the valvular element are eliininated, and the character 
of the first eoimd made to reserahle that of the second.. Con- 
clusive observations on this [juint were made a few years ago 
by Dr. Flint, constituting part of an essay which reettived 
the prize of the Ameriean Ifelical ABsocialiou in 1858.' 

Tie following facts were developed in this essay : 

1. \f a tbkU'd hiindkcrcbiirf be iilaccd botween the stetho- 
ecope and integument, the first sound is divested of some of 
jt» most distinctive features- It lo&ca the quality of iuipul- 
leion, and presents a well-marked val Millar quality., 

2. In many instances, when the atutlioaeope is applied to 
the jiraecordta, while the aubjeet is in a recumbent p06.tHre, and 

■the heart by lurce of gravity ia removed from the anterior 
of tho thorax, the first sound becomes purely valvular 
In charaeter, and as short oa the aeeond. 

3. When the fetethoscope i^ applied to the chest a little 
difitauce from the point where the first sound is heard with 
its niaxiuium of inteneity, it will present only itg valvular 
element. 

' ACBTIS Flistt, /V£m Ena^ m /Ar Ilmtrt-fhaiifb in Utalth and DiKMt, 



203 



OQEGULATION'. 



These fiictB, to whit!] itc may add the modifications of 
the fii'st fioimJ in disense, so ft* to leave onl;? the valvular ele- 
ment, taken in totmoc'tioti with the fact that the first sound 
occurs wlieii the TeDtricleG contract, aud neceesarily acconi- 
panies the closure of the auriciilo-ventricutar valve?, &how 
pretty eonelusivelj that the^e valves produce at lea&t a cer- 
tain clement of tlio Boiind. In farther Bwpport of this o|iimon, 
Tvt have tlie fsiet that the fiif5t sound is heard with its maxi- 
mum of iutensity over the site of the valves, and is propa- 
gated downwards along the ventricles, to which the valves 
are attached. 

Actual experiments are not wanting to confirm the above 
view. Chnuveau and Faivre^ have euceeeded in abulisbiog 
the lirst sound by t!ie introduction of a wire ring through a 
little opening in the am-icle into the aurieulo-ventricular ori- 
fice, ao arranged oa to prevent the dosui-e of the valves 
"Wlien this is done, the first Eonnd ifi lost ; but on taking it out 
of the opening, tbo sound returns. These obeen'ori also 
abolished the tiret BfiuuJ |jy introducing a &mall curved 
teiiotomj-knife through the aurieulo-ventricular orilice, and 
dividing the cbordte teiidiuea?. In tliie exiieriraent a loud rush- 
iug murmur took the place of the sound. We has'e already 
alluded to the experimeiit of intnxlucing the finger through 
an opening in the auricle; if tliia be done, and the heart be 
aui^cultated at the eame tnne, tlie valvee will he felt striking 
against the finger iu miiaon with the first sound. 

The above observations and exjieriments settle beyond 
qiic'stioii the fact t/att thii elofur^ of the awiotd<)-vetUriinikir 
i\ihvs produivs one danent of thfjirst sound. 

The other elements which enter Into the composition of 
the first tHJund are not as prominent as the one we have just 
Considered, though they serve to give it its prolonged and 
*' booming " character. These elements are, a euuiid like that 
pi-oduced by any large muscle dming ite contraction, called 

■ C^ MI., pp. 3U and 81. 




CAUBB OF THE BOITWDS OF THE HEAHT. 



by some the muscDlflr mumnu-, and tlie sound produced by 
the irnimlse of the Leart agahnst the walls of tlie eliett. 

The innecular sound Imsj been recuguized bj AYuUoetoD, 
Zisennec, and others, and by Lacnnec was BUi>[ic)aed to bu 
the sole cansc of the tir^t sound of the heart. This observer 
attributed the first Bound tu the niusculiir action of the ven- 
tricJeSj and the second to the action of tlie anricles. There 
Cftu.be no doubt but that this ia one of the elements of thetiret 
fiotind ; and it is this which gives it ita prolonj^ed churaeter, 
when the stetbosctjpo is ii]jp!ied over the body of the organ, 
as the sound produced in nius(.']escontinueadurinii; the whole 
period of tJieir contraction. Admitting this to be an element 
of the first sound, we can understand how Its duration must 
necessjirily coincide with the venti'icular aystole. We can 
aj<^ii'eciato, alfio, bow all but the valvular element is elitninated 
when the stethoscoi>e is moved from the body of the heart, 
the muscular &ouud not being ]'ropagattid aa completely ae 
the Bound made by the eloenre of the valvea. 

The impulse of the heart agninBt the walls of the thorax 
aJso contribntca to prodtieo the firet sound. This is demon- 
strated by noting the dflierenee in the sound when the sub- 
ject i« lying upon tlie baek, and when he id upright ; or by 
interposiug any soft substance between the Btethoscope and 
the t.'Jj est, (ir by auscultating the heart after the sternum has been 
removed. Under these circuraBtances the fij-st sound hwes its 
booming charaetcr, retaininpj however, the muaeularelement, 
wlieii the instnunent is npjilied to the es]306ed urf!;au, ItwiiB 
thought by Mageudie that tlie shock of tlie heart against the 
chest was the sole cause of the first sound.' Thia observer 
maintained that when the stonmm is removed in a living ani- 
m»!, the first sound cannot be heard over the heart. This, 
however, 16 nut the fact; and though the element of impul- 
sion enters into the composition of the first sound, the view 
that it is the sole cause of this eouud is not tenable. 

The first sound of the heart is complex. It is pro- 

' HlLKB-IBtiWARDS, Ztfont Bur la Phffrtoltyie, etc., tome 17,, p. 3S. 



210 



CIRCULATION. 



(laced bj the fiut3<3cn closure of the anrlculo-vetitficular 
valves at the l>egimiing of the ventricular ejetole ; to which 
are Biiperadded the lau^eular sound, duo to the cuDtrantioD 
of the muscular fibres of the heart, and the imimlsion-Bound 
due to the shock of the or^an agiiiiiftt the hiiIIb of the thorax. 

The second Bound U Bira[.ile, It is produced by the Bud- 
den closure of the aortic and pulmonRrj semilunar valves, 
iinmediatelj following the rentricnlar syatole. 

It ifl of the gi'tatest importance, with reieretice to patliol- 
og}', to have a ulear idea of the currents of blood through the 
heart, with their extict relation to the Roouds and intervals. 

At tliB comuieuceuient of tho first eonntl, the blood is 
forcibly thrown from tJie ventricles into tlie pulmonary 
artery on the right side and the aorta on the lett, and the 
auriculo-ventrieular valves are snddenly clo&ed. Daring the 
entire period occupied by this sound, the blood is flowing 
rapidly tlii-ong!! the urtefial orifice*, and the auricles are re- 
ceiving blood slowty from the veuw cavEe and the pulmonary 
veins. 

Wliile the second Bound is produced, the ventricles hav- 
ing become suddenly rehired, the recoil of the arteriii! walls^ 
acting upon tlie column of blood, immediately closes the 
semilunar valves upon the two sides. The auricles continue 
to dilate, and the vcntrEclee ai-e slowly receiving blood. 

Immediately following the second sound, during the firet 
part of the interval the auriclts become fully dilated ; and. 
in the last part of the interval immediiilely preceding the 
first sound, the auriclea contract, and the ventricles are fully 
dilaied. This completes a aingle revolution of the heart. 




CHAPTER V. 

FHEQUENOT OF T[IE HEARt's ACTION. 

Fnquencj of the beart'e actton^-Influencc of age — Influence of digestion — IiiBit 
ence of poeture and musculftr exertion — Influence of exercise — laflueuce of 
temperature— Influence of respiration on the action of the heart — Cause of 
the rhTthmical contractiona of the heart — Influence of the nervous system on 
the hesrt — Dirision of tho pneumogastrics — Gnlvanization of the pneumogas- 
tricfl — Causee of the arrest of action of the heart — Blows upon the epigaa- 
trium. 

frequency of the ITearfs Action. — PhysicianB have al- 
ways attached the greatest importance to the frequency of 
the action of the heart, as one of the great indications of tlie 
general condition of the syetem. The variations wliich are 
met with in health, dependent npon age, sex, muscular activ- 
ity, the condition of the digestive system, etc., point to the 
fact that the action of the heart is closely allied to the vanous 
fnnctiona of the economy, and readily sympathizes with their 
derangements. As each ventricular systole is followed by 
an expansion of the arteries which is readily appreciated by 
the touch, it is more convenient to study the succession of 
these movements by exploring the vessels, than by examina- 
tion of the heart itself. Leaving out certain of the qualities 
of the pulse, this becomes an exact criterion of tho acts of the 
heart. 

The number of jmlsations of the heart is not far from 
seventy peV minute in an adult male, and from six to ten 



212 



cmcuLATioy. 



more in tlie female.' TJiere are iniHviJual cases where tbe 
pulse is uuniiELUy iimcli slower or mure frequent tlian this, a 
fact which innst be remembered when examining the pulse 
in dUcase. It \a &ai(3 that the pulse of Nfipaleon I, was only 
furty per minute. Dr. DungHsou mentions a case which 
came under his own observatici], in which the pulse was on 
Hii aTerage thirty-six pur niiuiitc. Tlia same author states 
that the pulse of Sir William Congrevo was never below one 
hundred and twenty-eight per minute, in health." It is hy 
no means unfreqneiit to lind a healthy piilse of a hundred or 
more per minute. 



JnfiutncA cf Ag<$ and. S^x. — ^In both the male and female, 
observei-fl have constantly i(>uud a great difference in the rapidi- 
ty of the heart^e action at diii'ereut periods of li i'e, Tlie oliserva- 
tions of Dr. Guy on thi& point are very numerous, and were 
made with the ntmostt.'are with re<,'ard to the eoodinonB of the 
Byetem,atthe time the pidse was taken^ in each ease. Alt were 
taken at the saraehonr, and with the subject in a sitting posture, 

Dr, Gil J found the pulsations of the lieart in tbe fwtus 
lo be jiretty uditWrmly 14<I per minute. At blrtli the pulse 
is 13<j^ It gradually diminishes diiriog the first year to about 
128. The second year the diminution is quite rapid, tho 
tables of Dr. Guy giving 107 as the mean frequency at two 
years of age. After the seeond year, the frequency progress 
sively diminishes until adult life, whtin it is at its miin'mum, 
which 19 about 70 per minute. It ie a common, but erro- 
neous, impression that the pulse diminishes in troqueney iu 
old age. On the eorttrarj-, numerous observations show tliat 
at tliG latter periods of Hfe the movements of the heart be- 
come slightly atTe!"?rated, ranging trom 75 to SO. 

Duriog early life there Je no marked aitd constant difler- 

' Mont of the &4!U which <rill h» refanvd to with regard to the freqnencj of 
the pulac lire Iiik4-a fmtu (lie article of Dr. Gur (Pulse) in Todd'a Cjcloppdi* of 
AnlltOiDj iiml riiyBifllggy. 

* IJumaa Plitfnoloffif. Plii!»delph3a, IS.Ii^, viil, i„ ji. «5. 



FEEQDENCY OF TBE DEAItT 8 ACTION. 



213 



ence in the rapidity of the pulse in tlie sexes ; but teward 
the age of puberty, the development of the sexual pecnliarities 
is accompanied with an acceleration of the heart's action in 
the female, which eoutinues even into old age. The differ- 
ence at different ages is shown in the following table, eorn- 
|)iled by Milne-Edwards from the observations of Dr. Guy : ' 



Aon. 
From 2 to 7 yean 


Male*. 

Artrtgo Pttlntloi] 1. 
97 . 


FCULM. 

ATsngft PalMtloni. 
98 


" 8 " 14 


11 


. 84 . 


. 94 


" 14 " 21 


(1 


. . 76 . . 


82 


" 21 " 28 


It 


. .78. . 


. 80 


" 28 " 85 


11 


. . 70 . . 


78 


" 8S " 42 


11 


. SB . 


. 78 


" 42 " 46 


It 


. . 70 . . 


. . 77 


" 49 " 86 


It 


.67. 


. 76 


" 66 " 68 


11 


68 


. . 77 


" 68 " 70 


11 


. .70. . 


. 78 


" 70 " 77 


1. 


67 . 


81 


" 77 " 84 


(1 


. 71 . 


. 82 



Influence of Digestion. — The condition of the digestive 
BjBtem has a marked influence on the rajiidity of tlie pulse. 
According to observations cited by Milno-Ed wards,* there is 
an increase in the pulse of from five to ten beats per minute 
after each meal. Prolonged fasting diminishes its frequency 
from twelve to fourteen beats. Alcohol first diminishes, and 
afterward accelerates, the pulse. Coffee is said by the same 
author to accelerate the pulse in a marked degree. It has 
been ascertained that the pulse is accelerated to a greater 
degree by animal than by vegetable food. Tliese variations 
have long been recognized by physiologists. 

Influenm of Posture and Muscular Exertion. — Tt has 
been observed that attitude lias a very marked influence upon 
tlie rapidity of the action of the heart. Experiments of a 

' £*{mu tur la Phytiologie, tomcW., p. 62, 
* Loe. eU. 



214 



CIBCCI^TTON. 



very interestiiig; cliaracter have been umde bv Dr. Gny anJ 
others, with a view to detemnne ttie difference in the pulse 
in different postui*ea. lu the male, there is a difference fif 
about tc'u beats bctweeu stniiding and sitting, aud fil^eeii 
beats between etftudiii;^ and the recupibeut poature, la the 
teiiiale, the variations with position are not so great. The 
average given by Dr. Guy is, for the male: standing, 81; 
sitting, 71 ; lying, 66 ; — for the female : standing, 91 ; sitting, ■ 
84 ; Eying, SO. This is given as the average of a large num- 
ber of obsen-atiooa. There were a few instance, however, 
in which there was scarcely any variation with pasture, and 
some iu which the variation was much greater than tiie 
average. In tlie inverted posture, the pulse was found to be 
redm-ed ahoiit hflcen lieata. 

The question at once suggests itself whether the accelera- 
tion of th» pulee In sitting and standing may not be dne. In 
Bomo measure, to the muscular effort required iu niaking the 
change of postnre. This ia answered by the fartber espcri- 
menta of Dr. Gny, in which the eubjeets were placiKl on a 
revolving board, and the posture changed without any niu^ 
cular effort. The same resultfi as those cited above were 
obtiuned in these experltnents ; showing that the difference 
is due to the po&ition of the body alone. In a single obser- 
vation. Dr. Guy found tlio pulee, standing, to be 89 ; lyijig, 
77; difference, 12. With the posture changed without any 
muscular effort, the results were: standing, 87; lying, 74; 
difference, 13. 

Various theoretical explanations of these variations have 
been offered by iihysiologists; hut Dr. Guy e«^m9 to have 
settled experimentally that the acceleration is dsie to the mua-' 
cular effort reijuircd to maintain the body in the eittitig and 
standing positions. The following are the result-s of experi- 
utenta which bear conclusively on this point, in which it in 
shown that when the body is carefully supported in the erect 
or sitting posture, so as to be maintained without muscnlar 
effort, the pulse ia less freqiient than when the subject is 



TFXC 



215 



BtandiDg; rrad fartbermore tliat the pulise is acL-elerated, ia 
tlie recumbent posture, when the bmly is only partially sup- 
ported : 

" 1, Difference between the pnlae in the erect posture, 

without fiujiport, and Icimiiig in the same posture, iu tin 

avera^re of twelve experimeiitB on the writer, 13 beats; and 

on ao average of eight experiments on other healthy males, 

. 8 beats. 

" 2. Difference in the frequency of the pulse in the recum- 
bent poeture, the body fully Biipported, iiml partially BUp- 
ported, 14 beats, on an average of tive expei-iments. 

■" 3. Sittiii"^ posture (rneau often experimentaon the "ivriter), 
back supported, 80; unsupported, 87; difference, T beats. 

*' 4. Sitting piOBture with the legs raised at right angles with 
tlie body (average of twenty experiments on the writer), back 
unenpported, SG; supported, 68; difterence, 13 beats. Ad 
average of lifteen experimeuta of the same kiuU un other 
healthy males gave the following numbers ; back unsupport- 
ed, SO ; piipportedj OS j a difference of 12 heats." ' 

Iftjtnenec of Ejef^i^ciss.- — It ia a fact generally apprcL-iated 
that uiHSfular exertion Increaees the frequeucy of the piil- 
Bationa of Uie heart ; and the expenmcnfs juet uitwl eliow 
that the difference in rapidity, wbieh is by Bome attrihnted 
to change in posture (some positions, it is fancied, offering 
fewer obstacles to the current of blood tlian others), is in 
reality due to musoiilar exertion. Every one knows that the 
action of the heart is muth mure rapid after violent exertion, 
tuch as running, lifting, etc, Experiments on this point 
date fruiu C|uite a remote period. Bryan Kohinfion, who 
published a treatise on the "Animal Economy" in 1732, 



' Tnnn's CffrhpfciHa of Anatotnit and Phyt'toJOff)/^ vol. it^ p. 188. Tbeiv I> 
»t] ai>7)uiTnt canUraiJictjiia bi>twc'Gii th(.-i<« ^t^i^u]t9, and rc-fulu of llie CXpeniutrDU 
*itl» tb« " rCTOlving bfiard," It ia probiiklG, liowmer, llwt Oie subjct'ls «xp«i> 
ruuuied upon wiih the bonrd nere lintpl.r plnved in the eruut [lueture without 
uuHmkr fSut, iiul tcjamUiuuil llicinselrea in poaUion iritlioul irov uid. 



316 



C3BCCLATH1N. 



states, as the result of obAervntion, tliat a man in tlie reeum- 
bent position bae G-t puls&tions per minute; sitting, fiS; 
after a slow walk, 78 ; after wnlking four miles iu an how, 
100; ftiid 140, 150, or more, ntlur rtmtiing as fast as lie 
can. Tliia genera! stuteiiient, which has been repeatedly 
verifieil, shows the powerful influence of the muacuLir sya- 
tern on the heart. The fact is BO familiar tliat it need not 
be farther dwelt npou. 

Tlie inflnenL-e of sleep upon the action of tlie heart redncea 
itself almost entirely to the prripoeition, that during this con- 
dition, we have an entire absence of mu&cular effort, and 
coBsequently the number of beats ia less than when the in- 
dividual is aroused. It has been found that there ia no differ- 
ence hi the pulse between S'leep and perfect quiet ia tho 
reenmbent posture. Tliis fact obtains in tlie adult male ; but 
it is said by Quetelet that tliere is a niai'ked difference in 
femules and young eliildren, the pulse lH?ing always slower 
during sleep.' 

Injiuence of T^mpemiure. — The influence of extremea of 
temperature upon the hewl is very decided. The puUe may 
be doubled by remaining- a very few niinutea exposed to ei- 
treme heat. Deuce Jones and I>ickiuBon have ascertained 
that the pulse may be very much reduced in frequency, for 
a Bhort time, by the cold douche.' It has hIso been remarked 
that the pulse is habitually more rapid in warm than in cold 
climates. 

Though many circumstances materially affect the rapidi- 
ty of the heart's action, they do not complicate^ to any great 
extent, oui' exaniinations of the pulse in disease. In cases 
which present eousiderable febrile movement, th» patient is 
generally in the recmnbent pasture. The rariutions induced 
by violent exercise are easily recognized, while those depend- 
ent upon temperature, the condition of the digestive sy&tem, 
etc., are an alight that they may practically be disregarded, 

' R&BiNaOK, Animiil tEMMtny, Duhljti, USE, p. 117, 

• QirmLKT, Hur fhcmmr^ Bruxtlles, 1736, tomo iL, p. M, 



DfFLlTENOE OF BESPIBATION OM THE HEART. 



21T 



It is necessarj to bear in rnioa^ howerer, the variations which 
exist in tlio si?!te3, and at different periuJs ut' life, as well as 
tbe pft&iibility of Individual peculiarities,, when tlie action of 
the heart may be extraorilinarily rapid or slow. 

lufitienoe of Rcttplratum upon iJts Aeii&n of the Il«art. — 
The relntiona between the tunctions of circulation nnd i-eepi- 
ration nrc wry intimate^ One function cannot go on witiiout 
the otlier. If eircidatioB be arrestedj the iimstrleB, being no 
longer supplie<.l with fresh blood, soon lo&e their contractile 
power, nnd respiration ceases. We shall nlso find tliat cirt'U- 
Intion ia impijssiblc if respiration be permanently arrestetl. 
When i-eapiration is imperfectly performed, the action of the 
lieart is slow nnd labored. All ]»hy6iclan& are fainiliflr with 
the filow, full pulse, titdicatmg labored action of the heart, 
which occurs in profound eoma. Tlie eflecta of arrest of 
respiration are marked in all ]iart3 of the circulatory syRteni, 
arteries, cajiillaries, and veins; bnt the disturbances thus pro- 
duced all react U]>on the heart, and the modi tica6i one which 
take place in the action of this organ are of the greatest in- 
terest and importance. 

If the heart he exposed in a living animal, and artificial 
respiration be kept np, though the piileations are increased in 
frec|ueucY and diminished in force, after a time they become 
perfectly regular, and continue thus as long eis air h adfr- 
qnately supplied to the lungs. Under theae circumstanced 
we have tlie reejfiration entirely at our command, and can 
Btudy llie eflecta of its arrest upon, the heart with the greatest 
facility. If wo ari'est rcsiiiration, we observe the following 
clmngPB in the action of the heart : 

For a few seconds pulsations go on as nsiiel ; hut in abont 
a minute they begin to diminieh in frc(pieiicy. At the same 
time the heart becomes engorged with blood, a condition 
which rapidly increases. For a time its contractions ar« 
competent to discharge the entire contents ot the left ventri- 
cle into the arterial eyBtetn, and a eardiomeler ap}>Iied to an 



21S 



. CIBCtXATION. 



arterj will ixKiicate a great increase in the pressure of hlood, 
and a correspoudiiig incj'es^e iu tlie moTcuieara ot' tLe mer- 
cury will be noted at each action of the heftrt; indicatiug 
timt the organ in acting with an abnontial vigor. If res]>ti'a- 
tioTi 1x5 BtiM discantlnued, the engorgement bctsomefi intense, 
the hoart at eacli diastole being distended to its otmost capa- 
city. It now becomes incapable of emptying iti^clf; the con- 
tractioni5 become verj unfreqnent, perhaps tliree or fnur in a 
iriiniite, and are progressively enfeebled. The organ is dark, 
abiiost hlaek, owiug to the circulation of renoua bWd in its 
aabstauce. If resjilration be not reaimitHi, t!iis distention 
continues, the contractions become lese frequent and more 
feeble, and in a few minutes entirely ce^ie. 

The arrest of the action of the !icart, under these ciirum- 
atanccs, IB chiefly medinnical. The nnaurated blood paatea 
with dit!icnlty through tlie capillaries of the system, and a^ 
the lieart is constantly at work, the arteries become immensely 
distenided. This is proven by the great inercnse in the arte- 
rial pressure, while these vesaeU are full of black blood. If 
wo now closely examine the heart and great vt>BSels, wo are 
able to note distinctly the order in winch they become dig- 
tendefl. These jihenomena were particularly noticed and de- 
scribed hy Trof, I>aIton, and they dcmoiietrato coudusivx-ly 
that in H.spb^'xia the obstruction to tbecircidaliou crHiiniences, 
not in the lungs, ae ia commonly supposed, but in the capil- 
laries of the aystera, and is propngatc<l backward to the heart 
through the arteries. 

**Tbe php.tflele to the passage of venona blood through the 
capill&ried, therefore, ia partial, not complete. But it is stiU 
sufficient to produc-c an iiumodiate backward engorgement of 
the arterial eystem. Then the aorta becomes distended at ita 
Drigin, and the left ventricle and left auricle in eaccession, 
being unable to relieve thenusctvc!) cuf blood through the arte- 
rial system, become distended in a similar manner Ihuing 
thiii lime the name kind of engorgement takea place in the pul- 
monary artery »ind the right cavitioa of the heart ; though 




ENTLrBKCB OF EKSPIHATIOS ON THE HEAET. 



219 



the disteiition of tlie piilraoimry artery is never bo excessive 
as tliat of the aorta, cither Leaiiise there ia less obstacle to 
the passage of tctious blood through the lunga than tbroug'L 
the freneral eapillaries,, or hecanse tlie iiijcrrtlHg force of the 
right ventricle is less thim that of the left, yr because lees 
blood is supplied bj the capillaries to the veinSj and hj the 
veins to the right side of the heart. In cither case the prin- 
cipal acciiinulBtion ie certainJy in the arterial ey&tem." ^ 

The distention of the heart in asphyxia is therefore due to 
the fact that uniiemted blood cannot eirculate in the systemio 
cftpilhines. When thus distended; ita muscular fibres become 
pju'ftlyzcd, like any muacle after a Revere strain. 

If respiration be resumed at any time before the Iieart's 
action lius entirely ceased, the organ in a few monients re- 
E-auies its normal function. "We tiret notico n change fixim 
the dusky hue it haa assumed to a vivid red, which is owing 
to the eiitiilation of arterial blood in its capillBrte?. The 
difllC'Jition tiien beeonjes griijiially relit^ved, and for a few 
inomenU the puleatioiiB are abnormally frequent. If we now 
open an artery, it will be found to eonlnin red blood* An in- 
fitniment apjilied to an artery will show a diminution of 
arterial jircfisure and force of the heart'a action, if the arrest 
of respiration has been carried only far enongli to moderately 
distend the heart ; or an increase in the pree^^ure and force of 
the heart, if its action has been nearly arrested. A few mo- 
ments of regular insufflation will cause the pukations to re- 
Buuie their normal charaeter and frequency. 

In the human subject, the effects of temporary or perma- 
neut arrest of respiration on the heart, arc undoubtedly the 
same aa tliose observed in experiments upon the warm-blood- 
ed animals. In the aame way, also, it is po^ible to restore 
the normal action of the organ, if respiration be not too long 
anspen4]ed, by the regular introduction of frcali air into the 
lunga. The numerous examples of animation roetored by 

' DaltiiS, Lrdurn on tha Phyialagj/ nf the CiretdaHon, ptibliiilied in t|ie 
AjfTofe M^',<^ Journal and ytio Tark Jtevitv, Lecttero m., April, 1860, 



220 



CmCULATlON. 



artificial respiration, in drowning, etc., particularly by what 
is known as the Marshall Hall method, are evidence of this 
fact. In Cases uf asphyxia, tho^ measures by which Artificial 
respiration is most effectually mamtained have beeu found 
moat efficient. 

Certain iudividuala have the power of temporarily arreat- 
ing the action of the Iienrt by a voluutary suBjMjnsion of re*- 
piratioo. The most ir'niarkahle case of this kind on r«wrd 
IB that of Colonel Townshend, which is quoted in many 
works on physiology.' Cul. T. wa3 said to be able to arrest 
respiration and the action of the heart so completely as to 
fiiraulfitc death. When in thia condition, the poldo was not 
perceptible at the ^vrii*t nor over the prtecordta, a njirrorheUl 
before the month was not tarnishedi and he was to aJl ap- 
pearancee dead. On one occasion, in the presence of several 
medical gentlemen, he remained in this condition for half an 
hour I afterward the fiinctions of respiration and cinailation 
becoming gradually reestablished. This, to say tlie least, is a 
very remarkable ca&e, but is credited by many physiologists. 

Cause of the HhijiJimical Coniracttona of thfi Heart. 

Tlae pheiioinetia uttendisig llie action of tlie heart prv- 
seut few difficulties In their investigation, compared witli the 
study of the cauBeof the regular contractions ami relaxations, 
which eoinnience early in fcptal development^ to Icrmiuate 
only with life. This interesting question has long engaged 
the attention of physiologists, and has been the subject of 
nnmerous experiments and siteculationB, It would be idle 
to follow tlie various theories which have been ottV^nKl \ja 
account for this con&tant movement, except as a snbjec^t of 
purely historical interest; for many of them ai^ bjised upon 
B very imjHjrfect knowledge of the jihenomcna of the circn- 



' Ddsglibok, Haman PK^oloj/y^ PhiiadelpblA, 1850. Eighth eillcion, roL L, 
6.408. 



LraE OF THE BHITHMICAL OCflTraAPnOHS OF THE HEAHT 521 



lotion, and ]wivc fallen to tlie ground, as at;ieiiee'lia5 advani;otl. 
At tlie -preseut djiy, tbou^'li we arc perliaps as far as ever 
from a knowledge of the actual cause of tlie rej^iilar move- 
ments, we are prettj- ^ve]l acquainted vrhli the variuiis condi- 
tions wliicli niinlify and regulate theui^ and bave arrived iit a 
limit of knowledge which tlierc &eeni8 little proepect of ex- 
ceeding. The entlmeiastic dreamera of past agee hojwd to 
discover the seat of the soul and arrive at the principle of 
lif'ej hut we are as mucli in tlie dark as were they with regnrd 
to tho eause of the varioim vital phenomena. AV^e know, for 
example, how to iiidiiL-e contraction in a living mnscle, or 
one which is just sepurntcd froru the or^iuiiiiui and has not 
yet lost what we eall its vital properties, bnt we mU6t confess 
our utter ignorance? wht*n we ask onrsolves why it acts 
in response to a stimulus, The wonderful advances we 
have made in chcraiBtry and niicroBeopiu auutomy do not 
diseloee the vital principle ; and when we come to examine 
the various conditions under which the heart will coutiane 
its contractions, we are arrested hy the impossibility of fathom- 
ing the mystery of the cause of contraction. The heart is, 
atiatoinlcftlly, verj- mnch like the vuhmtary mtisdes; but it 
has a constant function to perforaij and will act without any 
palpable excitation^ while the latter, which have an occa- 
sional function, act only under the influence of a natural 
stimulus liko the nervous force, or arttticial irritatitm. 
The movements of the heart are not the only examples of, 
what seoma to he, spontaneona action. The ciliated epithe- 
lium is in motion from the beginning to the end of life, and 
will continue tor a certain time even after the eells are de- 
tachtfl from the organism. This motion cftunot beexplaincd, 
un]^« we call it an expla.nation to eay that it is dependent 
on vital properties, 

Bnt if we ore yet ignorant of the absolute cause of llie 
rhythmical contraction of the heart, we are pretty well ac- 
quainted with the influences which render its action reguhir, 
jtuwerfnlv and Rufficient for the jiurposea of the economy. It 
IB 



222 



CIKCCLATIUS. 



will facilitite our conipreLensJon of this, to compare this 
action witli tliat uf the LinJiuarj voluntary muscles. 

Ill tlie first platie^ every one knows that the action of tlio 
heurt 19 iuvoluntfii-y. We eaa nt'itLier arrest, retard, nor 
accelerate its pulsatioiia hy a direct eftoil ot' the will. In tbia 
etatement ive ot' course esc-ept tlioae examples of arrest hy 
the stoppage of respiratioa, or acceleration by violent eser- 
cise, etc. In this respect the heart tliU'ers from certiiin muft- 
cles, like the muscles of respiration, which act involuiiturily, 
it ia true, but whose action may he teniporarily arrested or 
accelerated by a rlirect voluntary effort. 

The last -mention e*] Ijift gives ue the preeiae difterence 
between the heart and all other striped mnscIeB. All of 
them, in order to coiitraL't, nuwt recdve n fetimulus, either 
iitttunil or at'titieifll. The natural stimulus comes from the 
nervous centres, and is conducted hy the nerve*, If thenervea 
going to any of the respiratory musdos, for example, be 
divided, the muscle i& paralyzed, and will not contract with- 
out some kind of irritation. Connection with the nervous 
Gvstem doe« not seem neueBfiary to the action of the heart, for 
it will contract, uspec^ially in the cold-hloodcd anitnaU^ eouie 
time alYer its removal from the body. 

When a miisclo htu'j been removed from the body, and is 
Bubjected to a BtimuliiB, such aa galvanism, incchatiical or 
chemical imtatlon, it i* thrown into contraction ; but if care- 
fully protectefl from irritation, will remain quiescent. Con- 
tractioa in this instance is evidently produced by the appli- 
cation of the stimulus ; but the question arises, Why <loe6 the 
muscle tbua respond to etimulfttion i This is a question which 
it i& impossible to nuflwer eati^sfactorily, but one conccruing 
which our ideas, since the time of ITaller, have aseumcd a 
defiuile form. Tliis prcat physiolog-ist i-ulled the property 
which cauaes the muscle thus to contract, irrituhiUty ; which 
is notliing more nor less than an unexplained property in- 
herent in the niugde, and continuiutx afi long as it retains iXa 
absolute physical and clieuiical integrity. More than a hnn 



w THE RirmisncAL ooNTKAcrrtosr 



fHEAET. 223 



(Iretl jeiiti Hgo, Ilaller deat;i'il>ed certain tisBues of the body 
wbicli possessed t\m "■irritability?," such as the muBclea, 
&toinac-l«, bladder, eti-'., and the diflerent degrees ofirritfibility 
with which each one was endowed.' He applied this theory 
to tha action of the heartj wbicl; he conBiclered aa tlie part 
endowed with irritability to the highest degree. His theory 
of tlie action of the heart was that its rhythinical contraction 
d<?pende<l upon the irritabilifjinhcrc-nt in ita inusRular fibres. 
He was far froui denjiiig the vancnis influences which modi- 
fied this action, but regarded its actual power of contraction 
OS independent. It will be interesting^ to reriew eonie of the 
faots which were estabhshcd by Ilalh^r, and by nuiiit?rous 
physiologieta who have since investigated this subject, and 
Bee how far this view of the independence of the contractile 
power of the heart accords with the present atate of our 
knowledge. 

Expertinents hate shown that the heart will pideate for a 
time when remoTed from all connection with other parts of 
the orpaniam.' In the cold-blooded auimale, in which the 
irritability of tlie tissues remains for some tiiuo after death, 
tliis is pfirticnlnrly marked. It is uot the blood in tlio eavi- 
tic-s of the h\;art which canses it to contract, for it will pid- 
eate when its cavities have been emptied. It ia not the con- 



' Haller, Mtmnire* KUr !a A'aturt Snt*ihtt et frritattf de» Partie* iftt CoTpa 
Aahna/, Lau.^juine, 1756, lome L Tlx^se vii^-wa niili ttguni to the dUHse of th* 
nctioii of Ibc boirL were &rst aih'unct'd h\- HiilItT 3ii 17ltff io coimtneDtlU'ic^ on t]iO 
" l-nalitutc-s " of IJocThaiiTL- (;Ifiui. tie IIaller, p. 87). 

^ N>iiiii'roa§ inslanct'j of roDlructitrns ol'tbo bourt ia <^ali]-hliioili.'i! aciimubs t'Oiv 
tinoing for » very lon^ lima after ^^spision, are on rti'ord. Dr. UuDj^lison, ia hjB 
WtfTJc on Phyiiiology (op, pit,, yoJ, i,, p, 408), meutiona spheral instaneiM Tfliure titti 
Iwan pulsntcd for from teu to twcnty-fuur boiir& nAtr rcmovnl from tliq Ikk);. 
The m^i n?Tn4Ttiablo ciiuD|)I:ea of Uib |iroloDged action were in Ciie heurt of the 
■lurgROa, lu ontiiLsUinc?, inaiiexpi'i'iiiicnt tiiialiLr^uIli||;ivCDr, ncfoimd tbfibuart 
pulsiLiiiij;, •>«■(«, t»-erilv.eLg]iilioura after the auiiiml bail been kUleJ by the Injw- 
rlon of & SOlutiOQ of Koornni. Tlie Itcnrt wnS ttiL-Il cxdscit, tmd OOBtitllleil U> 
best durin.^ • loiig fcrios of eipcrimenta, until it was nn'edtAd bf povetAil Cotnpro* 
noD with tbc hnjid^ after it hsxl been filled idtb waiter and the Teasels Lied. 



224 



OTBOCLATIOS. 



tact of the air, for the heart will puUiite in a Tacuuin.' The 
heart does not receive its irritability t'roiti the nexvous sya* 
tcm, for, when j-eiao^ed Irani the body, it has no conuuctioa 
with the nervous system ; and it ia not probable that it r&- 
ceives any iiifluenee from Rvnipathetic ganglia which have 
lately beeu i.llseovei'etl in its eubstance, tor iletachcJ portions 
of the heart will pulsate, and tho eoutraetiuiift of the or^an 
will eotitiuue in aiiiraala poiscned with woorara, whieU is 
known to paralyze the motor sy&teni of nerves. 

It is unat-fcssary to refer to the varioua ex]>ctriiuenta 
which have clcinonslratcd tlie inOe pendente of tlie eonlrae 
tions of the heart. They are of such a eimpio iiaturc that they 
may he verified by any one who will take the trouble lo ex- 
cise the heart of a frog or turtle, place it under a small Lcll- 
glasa BO that it will not be subject lo possible irritation froin 
currents of air, aJid watch it* pulsations. In such an oljiserva- 
tion as this, it is evident tliat for a certain time contraetions, 
more or less FL'guIar, will take places and the experiments 
referred to above ehuw that they take place without any ex- 
ternal influence. In &hort, it Ib evident that ihe niu^^ular 
fibres of the heart poBsese an imtahility, by virtue of which 
they will contract iuterniiMcntlj' for a time, tJwiujh no etlm- 
uhm he. applml ; as ordiiuiry striped muacular fibres have an 
irritability, by virtue of which they will respond, tor a time, 
to the application of a stimulus. 

It is laanife&tly necessary that the action of the heart 
Bhould be coustiint, regnlar, and powerful ; and when we say 
that the irrituhility inherent In it£ ningeular lii^sne its eueh 
tliat it will contract for a time without any external siimulus, 
we by no means assume tluit this is the cause of ita pfiym^og- 
tool action. It is only an iiujiortaLt and incontestable proji- 
erty of the muaenlar tihres of the heart, and its regular a/^ion 
U dependent upou other circumstauces. 

In the tirst place, we have to inquire what makes the ac-' 
tion of the heart constant. Tlio answer to this is, that the 

' Joii* Rkio, in Cylopirtlia o/ Aaatomi/ and Phi/tutUiffif, vol, 11,, p.QI1. 



CAU8B OF THE HHTTHanOAI. COSTSACmcmiS OP TOE HEAHT. 

cimngea ofriutritinii, hy which, throiigli the blood circulating 
in its suhstant'e, tUe -waste of its tissue is constftotly supplied, 
preierves the integrity of tlie filjrefl, and kt>eps tbem^ conse- 
quently, in a, condition to contract. Tliis is true, likewise, 
of the ordiiinry strijicd miiBruliir iibrea. If the supply of 
blood be cnt ofl' from the siib3tnn<.':e of the heart, especially ia 
the wann-blooded animnis, the urgau soon loses its irrltabii- 
ity. This was beautifnlly ehowu by the oxperimeots of 
Eriehaen. This observer, alter exposing the heart in a warm- 
blooded animal and keeping np artificial respiration, ligated 
the cororiiarj arteries, thus cutting off the greatest part of the 
supply of blood to thy inuscuhLf fibres, lie found, as the 
mean of eix experiments, that the heart ceased pulsfttLng, 
thougli artihcial respiration was continued, in 23^ uunutes. 
After the pulsationa had ceased, ihey could be restored by 
retaoving the ligatures and allowing the blood to cireulate 
a^ain in the substance of the heart.' The same is true of the 
irritability of ordinary muBcIca, m haa. been lately shown by 
the experiments of Dr, Browu-Setjuatd, though the continu- 
ous action of the heart nndoubtetUy canses theae phenomena 
to l»o more marked and rapid, If M'e take a muscle whicii 
has^ ju-st lost it& irritability and will no loiigei' f«8i>nnd to the 
mo6t powerful t^tiniulue, and inject fresh blood by the artery 
supplying it, the irritability will be inimediately rt'&tored.* 

In the eeeond ylnce^ f/i£ rt'^ithir and /wwt'rful contraction 
of the h^iart is j>rov^'-dei.l for by thff ciiymlation qf the JAood 
ihrovfjh it^ caviti^'S. Though the heart, renioveil trotn tha 
body, will contract for a time witliout a stitmilus, it can be 
made to contract during the intervals of i-cpose by an irri- 
tant, Biich as the point of n ticcdfe, or a feeble current of gal- 
vanism. For a certain time after the heart has ceased to 
coatract Bpontaneously, contractions may be JEduccd in tliiis 
way. Tliis can ea&ily Ik; demonstrated in the heart of any 



' Londvn Mr^Jliyil OasrUf, July 8, 1844. 

• Bxows-'l5i«CAiu>, Propriitia ft Vioffta dt tang rotfQS ti >l" »'"ij "oir, 
Jovmal lit la I^i/»iotoffU, 1 BfiS, Lome i., p. K tt teq. 



CmcCLATIOK'. 

ftuimal, wjinn or cold-blooded. ThU irritabilitj, wlucli a 
niaiiifested, under these circum-itanees, iu precisely tlie Bam© 
way as in ordinary muaclcs, is different in degree in difiercut 
parts of tlie organ. Haller and others have abown that it is 
greater in the cavities than on the STirfaw; for laug after ir- 
rilatiou aiiplieJ to the exterior fiiiU to excite contraction, the 
organ will rcBpond to » stimulus applied lo its interior. The 
experiinentfl of Haller aha show that fluids in tho cavities of 
the heart have a remarkable influence in eseiting and keep- 
ing up its contractions. This observation is of mncb intweet, 
as ehowing condusively that the presence of blood is ueees- 
eary to the natural atid regului* aotiDC. of the heart. "Wo 
qoott' one of the experiments oit thid point performed upon a 
cat: 

(1 » « « Tjjg superior vena cava having been divid- 
ed, and the inferior ligated, and the pulmonary artery opened, 
and the right ventricle emptied by a sufficient eompresMon, 
and the aorta ligated, all with promptitude, I saw the right 
auricle repose first, the right ventriele continued to btat for 
some time In unison with the left ventri^-le^ and its walls de- 
6ceuded tuwai'i! the middlo line pt' the heart; but this vea- 
triele did not delay to lose its movement the first. As for 
the oilier veutrick, wbicli could no longer empty itself into 
the aorta, it vras filled with blood, and its movement contin- 
ued for lour hoiire. **■*"' 

This experiment was confirmed by numerous others. It 
will be observed tlmt one side of the heart waa made to eeaae 
ltd pnlsatioDft, while the other side oontinued to contract, by 
Biniply removing the blood from it* interior; which eoucUi- 
sively proves that, tltoagb the heart may act Ibr a time in- 
dependently, the presence of blood in (ta cavities is a stim- 
ulus capable of prolouging its regular pulsations, Scblffhaa 
gone Btill farther, and succeeded ia restoring the pulsations 
iii the heart of a frog, wliieli had ceased after it had lH?en 

' Bu.LtR,Mtnmr<» mr ia A'a^n Irritu^ d Senniit dei Portia, fff., lumo 
1., p. 868. 




CACBE OF TOE HHTTHMICAL CONTRACTTONB OF THE HEAKT. 227 

emptied, hy infrodin-'ing a few drops of blood into tlie au- 
ricle.' thir own experiments iiixjn tlie lieiiris of iilligatora 
and tartles eliovv that wlien removed from tho body mid 
efupticd of bloody (be pulsutioiia are feeble, rapid, and irreg- 
ulur; but tliat wlien filled with blood, the vah-es being de- 
stroyed so as tu nilow free passage in botli directions bt/twoen 
the iiurifles and ventriclOj the eontractions become powerful 
And regular. In these experimenta, when water Wiis intro- 
duced instead of blood, the pulsations became more regular 
but were more frequent and not as poirerl'iil as when blood 
■ft-iis liw^l.' These experiments show also that the artion of 
the heart may be alfeeted by the diaracter, partit'uhirly the 
density, of the tiuid which passes through it, which may es- 
ptuin i(a rapid and feeble action in ansemia. 

It seems well estabiisheil that the beiirt, though capable 
of independent netion, is excited to contraction by the blood 
as it piisi^ea through it4 cavities. A glam-e at the sut-cession 
of its movements, particularly in the cold-blooded animals, 
where they are w slow that the phenomena can be easily ob- 
Bervedj will eliow bow these contractions are induced.- If we 
look at the organ aa it is in iK'tiou, we see firat a disten- 
tion of the anricle; tiiis is iuimediately followed by a con- 
tractiou tilling tlie ventricle, which in its turn eootracte. 
L'ndionbtedly the tension of the tibres, m well as the contact 
of blood in ita interto]", acts as a atimnlus; and aa all the 
libres of each cavity are pnt on the etrotch at the same in- 
Btant, they contract siniultuneimsly. The necessary regular 
distention of eaeli cavity thus produces rhythmical and forcible 
uonti-actioti&; and the mere fact that the aetioa of the heart 
alternately eroptie* and dilates its cavities, insiirpB regular 
pulsations as long as blood is supplied, and no disturbing iu- 
tiuences are in oiJeration. 

The muscular tibres of the heart are endowed with 

' Milki-Edwarpk, 0?'. fit. lonie iv., p, 120. 

* Action of the Utart <mii UtitpirtUion. — Amrrican Jtumiai of rAr JftJicil 
%»RMC*, OcL IBei. 



228 



CIRCUHTION. 



on inherent property, called irritabilUtf, by \irtue of wiiidi 
tlioy "will contract for u certaiD thue without the appliication 

of a etiiiiulus. Irritiibility, niiinifettcHl in this way^ cfliitinuea 
80 luu^ US, by the proccssc's of nutrition, tbe fib-res are mutD- 
tftined in their integrity. The must^ular tissije, however, may 
be tlirowii into contraction, during the intervals of repose, by 
th6 application of a stimulus, a projierty wliich is enjoyed 
by all niu&cnlnr fibrea, The irritaLility manitei^tecl in thia 
way is mutb nioi'e marked In the intfi'ior than oti the exterior 
of the organ. Blood in eoDtiii.-t with the lining inerabranu of 
tlie heart acts as a stimulus in a remarkable degree, and ts 
even capable of restoring irritability ulltcr it has become ex- 
tinct. Tbe passage of blood through the heart is tbe natural 
Bliruulua of the orpan, and may be suilI to bo the causa of 
iis reg-ular pul.saUona, though it by no means endows the 
6hrea with tlieir contractile properties. 



Ivjiu&nce of Me Nermu9 Sy^imi on ilie Heart. 

The movements of the heurtj as we havD seen, are not 

directly under the control of the will; and observations on 
the human subjeet, as well h3 on living animals, have feliown 
that the organ is devoid of gcn&ral sensibility. The Utter 
faet was demonstratetl ib the most BHtisfactory manner by Har- 
vey iu tbe case ol' tlie Yificoimt Montgotnery. In tins t-a&L* 
the heart waa esi)0,4ed ; and Harvey fuund that it conld be 
touchoti and handled witliout even the knowledge of the sub- 
ject* This hna been veritied in other inetaniee-s in the biuu«n 
subject. Its physiokigieal movements are capabJe of being 
influenced in a remarkable degree through the nervous &yft- 
teni, not^vithatauding this iusensibility, and in spite of tho 
fact that the luuaeuhir fibres comjjosing it are capable of 
contim^tion when removed from alt connection with the 
body, aud thtit tiie regular pulsatioTi*. can be kept up for a 
long time by the mere jiasiBago of blood through its cavities, 
Tbe iutlueuco thus exerted is so great, that goiiie eminent au- 



IHKLUESCE OF THE SF-RVOUS SYSTEM OS THE BEAET, 221) 



tliorities held the opiuioti that tlie cause of tha imtitljility of 
the organ was derived from tlie iiervca. One of the nii>st 
diatingnisli&J advocates of" ttii& opinion was. Ley^allois, TUis 
observer arrested tlje action of the lieart of tlitj ritlAdt by sud- 
denly destrorbg tlie &[>iiial cord, from Tvliidi he drew tlio 
coTicluf^ion that the heart derived its eoiitraetile power from 
the oerehro-spinal pysteiii/ The experimenta whiflh we have 
already cited, showiug the continiiaiiee of the Iieiirt's nctioii 
after eseisioti^ dispi-ove tliis so coui]ili?tely, that it was nut 
thought worth while to dist-uss this view while treating of 
the caose of itd rhythtnioal contraction. The same may he 
paid with regard to the expcriinente of Brar^ihet, in which he 
endeax'ored to prove that the eotitractiUtj' of the heart is de- 
rives! from tlie cardiac plexus of the pynipathiitie fivstera of 
nerves. The fnct that tlie heart doea not depend fur lU coa- 
tractilitj niHin external nervous influence may be r^arded 
aa long fiince definileilj settled ; hut within a few years the 
discovery in its euhatanceof ganj^lia belonging to tlie sympa- 
thetic system has revived, to some extent, the view that its 
irritability U derived from nerves. 

It is not necessary to follow ont all the esperimentd ■which 
corobine to demonstrato the uicorreotness of this view. Ber- 
nard, by 3 Series of adnnrably-conceived experiments upon 
tlie efleeta of the woorara poison, has succeeded in (iuinon- 
stratin" the distinction lietween muscular and nervous irri- 
lability.' lu an animal liilled with this remarkable poisoo^ 
the functions of the niotur nerves are entirely abolished ; so 
that galvanization, or other irritation," does not ]iroduce the 
slightest etfect. Yet the inneelea retain their irritability, and 
if artiHcial rc-apiration be kept np, the circulation will eon- 
tttme for a long^ time. The heart, by this means, Beeiua to 
l>e isolated fruiii the nervous syntem aa completely ha if it were 
exaecd ; and galvanization of the pneumogaetnc nervts in 

' Lmj-allms, (Emfei, tome i., ^. 97, 
BchMaild, Lifont aitr Ir^ MffcU dt» Su&ttanMt Toxiquet d lifidicamtnUuittt 



230 



CmCTiXATlOS. 



the neck, ifIiicIi, in a lEviTig animal, will inimedtately arrest 
its acitiou, ]i!ia nu eifect. On the utiicr luind, iMiisoning by 
the Bnlphoyjaiiide of potassinm ilestmys the niusunlar irrita- 
bility, sinil leaves tin; nerves iutdct. Uy these experiment*, 
which we have frequently repeated, we can completely se]> 
arate the uervons fi'oni the loitseiilar irritability, and ftbow 
their entire iudcpenJence of eftch other; and there is every 
reosou to ^appose that the heart, like the other muscles, docs 
not derive its contractility from any ollter pystcin. 

It is evident, however, that the heart is often powerinlly 
influeucecl throu<;h the nerves. Sudden mid viuliUJt omotions 
will occasionally arrest its action, and have been knottii to 
produce death. Palpitations are to he a«f«unted for in tlie 
flame way. Some of the moditicatioxis which we have already 
coiisidefed, depending on exeroiiie, digeatioti, etc., are eflecteil 
through the nerr^es; and it is tbrongh this system that tlie 
heart, and all the important org'anB of the body, are made to 
a eertain extent mutually de|>endent, It Iieeoniea interesting, 
and highly important, then, to etudj their influences, and 
follow out, as clejirly as ])0i^&!blG, the action of the nerves 
which arc tlietribnted to the heart. 

The anatomical connectiona of the heart with the nenrons 
centra? are mainly through tlie symjiathetic and the pneu- 
mogastric nerve:-. "We can study the iufluenue of these nen'Bi 
to most advantage in two ways: iiret, by divitling them aud 
watchiiipc the effei-t of depriving the lieart of their iiiBuenee; 
and pcijond, by exciting tlienx by means of a fetihlo cnrrent 
of galvanism. It is well known that En an animal just killed 
the '"nervous fort'c" may he closely imitated by galvanism, 
which is better (ban any other means of stimtihition, ms it 
does not aff'et^t the integrity of the nerves, and the anioiint 
of the irritation may be easily regulated,' 



* We ihaU not illKiiaa Hie t^tx\a upon the heart of Budldca deatrnctton of thv 
great nenrous c«i<rM. It h»B boca abuwn (liat Uie bL-»rt bopotnc* amsM wh*n 

Ibe brmiii ia L'rtiiHlierl, na hy a blow wllh a haminor, irhon ih-Q nMaluIlii oMiiugnln ui 
t,h« spinal cord Lf fludd^Dlj (icstro?ed ; dnd «vtn ihv cnmhinj; pf a font, in lh« fro^ 



lOOASTKICB. 



Experiments oa the inflnence of the sympathetic nerves 
upOQ the heart are Dot quite as aatififactory as we niight 
desire. Brachet aeaerte tliat the action of the heart is imme- 
diately arrested by destroying the eardhie plexua.' With 
regard to this observatton, we must take into account the 
difficulty of making the oix'i'ation, and the disturbance of the 
heart consetiueiit upon the nece'ssary iqatiijmlatlotis ; cireum- 
etanees which take away mut,'h of Its value. It has been 
shown pretty conelutiively, howeier, that BtiJiiubitioii uf the 
sympathetic in the neck has the eftect of accelerating the 
piilsatimis of the heart.' The extretrie dItEfuttyof dividing 
all the branches of thesyrapathctic going to the organ leiu^es 
a donht aa to whether such &n operation would definitely 
abrid-re its action. 

We have nest to consider the influence of the pnenmo- 
ga^tricft (Jpon the heart. Esjj^riments on theae nerve* are 
made with greater facility than on the nerves of the sympa- 
thetic f>ytitem, and the results are much more satisfuctory. 
Liiie all the cerebro-spinal nerves, the influence generated 
ID the ner\'ous centre from whit-b they take tlieir origin 
IB conducted along the nerve, and matiifested at its distribu- 
tion. Wlion they are divided, we may be sure that, as tar 
as they are concerned, all the orgaiia wliich they supply 
are cut off from nervous influence; and when galvanized in 
their course, we biiitate or exaggerate the influeuee sent from 
the nerroas centre. 

The invariable effect on the heart of divifliqn ot the pneu- 
moga&tric nerves in the neck is an increase in the frequency, 
and diminution in tho force, of its pulsations. One or two 

hna bi-CD known W pTOciuee this effijcl. In fine, tliia may be done by any eiten- 
sire injury lo ihe ucntona nyatcm^ but thi* fuct does not tt'och iis jnucli with 
Rginl to the phfHQlogii/al iaflutni-ca of ihc uerre?. For c!itimpto, wMIc crash- 
ing of the brain arreata the heart, ilie hraia muy be rtrmoTcil from a Ii»inf,' animal, 
ta'i the beurl n-ill beat tot ilajs. Ex[>i;riiiicuU upon lL£ iotiueTii^ or tho med'ilL 
^btongiLtD and ipmkl cofA tfc bj no means gatisfactory. 

t Bmciirr, Syflimt Heruelfz yanglitnaire, BrUKeLlea, ISM, p. 1S8. 

' MtW^EDWiwis, Pfii/BiologU, Psris, 1856, tome it., p. IBB, note. 



232 



CIBOULATIOH. 



writere have denied this fact, but it is confirmed by tlie iesli- 
mcmy of nearly all eiporimenters. To ATiticipate a little in 
the liiRtory ol'the pueiimogastric tierves, It maybe stated tlint 
wlnle they arc esc]u^ively sensitive at tlieir origin, tbey receive 
after having emerged from the cranial cavity a nuiulier of 
filaments t'rnin varitnis motor nerves. That they influence 
certain rau&cles, is sliowu by their paralysiB after division of 
the nerves in the neck; aa, for example, tlte arrest of the 
movenienta of the glottis. 

TTaving tbis di^oble property of motion and seneation, and 
being distributed in jjart to an oi^ati composed almost exclu- 
aively of muscular tiUros. nhieh, as we liave eeen^ ia not en- 
dowed witli general scndbilitT, we slioiild expect that their 
Bcctbiti fl-ould arrest^ or at leust diunnisb^ the frtHjueneyof 
^e heart's action. What explanation, then, can we offer for 
the fact that this seems actually to excite tlie movements 
of the heart? We will be better prepared to atiawer this 
qxiestion after we have studied the effects of galvanization of 
the nerves in a living animal, or one in which the action of 
the beMrt is kept u]i by artificial respiration. 

Numerous experiments have been made with reference to 
the effects on the heart of galvanic currents, both feeble and 
IHiworfiil, pa'^setl through the pneurnogafetrics before division, 
of currents passed through the upper and lower extreniitios 
after divLeion, etc,, a full detail of which belongs properly to 
tiie pliyi^iological history of the nervous systtni. In this con- 
nection, a few of these facts only need be stated. 

- It has been shown by re]>eated experimenta, which we 
have frequently confirmed, that a moderately -powerlUl cor- 
rent of galvanism parsed through both pneutnogastries will 
arrest the action of the heart, and that the organ will cease 
\ta contractions as long as the current i& continuetl. This 
experiment has lieen performed upon living^ animals, both 
with and without expoanrc of the heart. The arrest is not 
duo to violent and continued contraction of the uiu&culat 
fibreBj on the contrary, Cho heart is relaxed, ita ventriclea an; 



JABTEICS, 



233 



flaccul, ami lU fibres are for tUc time paraljzeO. The quoa- 
tioD then arises whether litis action be directly exerted on the 
heart through the nerves, or whether an influence be conveyed 
to the nervous centre, and tranBinitted to the heart in another 
way. This is settled by the experiment of dividing the 
nerves and galvflnizing alternately the extremitiea connected 
witJi the heart and those connected with tlie ner\'OU8 centres. 
It liri5 been ascertained that jralvjmization of the extremitiea 
connected with the heart arrests its action, while galvaniza- 
tion of the central extretiiitl^ haa no such e^oct. Another 
intereating fact alao shows that the influence e.'terted npon 
the heart is through the motor filaments of the paeumagas- 
trics. It has been atown by Bernard, in a very cnriou& series 
of experiments which we shall not fully discuss in this connec- 
tion, that thewoorarapoition paralyzes only the nioturnerves, 
leaving the aeneory nerves intact. If we expose the heart 
and pnenraogastric nerves in a wflrm-ljlooded animal poi- 
ftoued with this ngent, and continue the pulsations by keep- 
iBg t)p artificial respiration, we find that the most powerful 
current of galvanism passed through the pnenuiogastrics has 
no effect upon tho heart. The effect of a leehle ciurent of 
galvanism upon the motor nerves is so like the operation of 
the natural btiimilus, or nciTons force, that for a time many 
physiologists regarded the two fore^ as identical. Though 
this view is not received at the i>reaent day, it is an admitted 
fact that by gjdvanism we imitate in the closest manner the 
natural action of tln^ motor nerves, and this has become a 
moBt valuable means of investigation into the physiology of 
the nervous systeni. 

Though galvanization of the pneumogMtrics arrests the 
action of the heart in nearly all aniiiiale, there are some in 
which this does not take place, as in biitlB; a fact which ia 
stated by Bernard,' bsit for which he otlers no esphmatiun. 
In some e^perimfente instituted on this subject a tew years 



234 



OIBOITf^TIOir, 



ago on alligatorB, we noticed a eingular peculiarity M-liicb 
throws some light on the question we are now considering. 

Dofliritig to demonstrate to the <'1a«» at tine New (li'leaoa 
School of Medicine the action of the heart in this animal, an 
alligator six feet in length was poisoned with woorara, and 
the heart expoBed. The animal came nnder the influenee of 
the poi&on in aliuut thirty minutes, when the dia&ectiou waa 
commenced, and was quite dead when the heart waa exposed. 
TIjo piiL'uniowastrica were then espoaod and galvanized, wltli 
the efl'eet of iironiptly arrestiiTig the aetion of the heart. This 
ohservation was vtrifiod in another experiment. Wc wero 
at first at a loss to aocomit for the absence of effect of the 
woonua on the motor tilanaents of the pneHntogastric nerves ; 
tint ou reflection thonghtit n]ig;htbeduetoslow absorption of 
the poJBOu in BO Iar{»e a cold-blooded nniiual. With a view 
of ascertaining whether there Is anj difference in the prompt- 
nesa witli whic^h difl'erent uon-es in tlie body are affeetcd by 
thia ugi^nt, we made the following experiment upon a dog. 
Tlie animal was ]>rouglit under the influence of ether^ and 
tJ]e heart, the pneumogastrics, and the sciatic nerve were 
exposed, Galtaniiation of the striatic produced moscnlar 
contraction, and of the pneninogaatrlc3 arrested the heart 
promptly. A grain of woorura, dif*&ijlved in water, was then 
injeeted under tbe skin of the thigh. One hour after the 
injection of the woorura, the sciatic waa found inBcnsihle to 
galvanism, hut the heart cotdd bo arrested hy galvanization 
of thepneuraogastrica, though it required a powerfnl current, 
A wealier curi'L'tit diniiiiiiehed the ftveqnency, and increased 
the force, of its pultsattoni?.' In tliia pxjjeriment, the opera- 
tion of opening the chest undoubtedly diminished tbe activity 
of absorption of the poison, and consequently retai'ded its ef- 
fects upon the nervous syatem. Taken in connection ivith 

' Tb'u increase in ihs Tqkx ot tbe lieni^ nhich iic«an>|>«nied the tliiuinutjos io 
Ihc fivKiuenc; of tls pubations, conacqucDt up<iu feeble galraniuHioa of thv paeu- 
mogasinui, wns dohviatiily 'Observed in nmy cxperiin^is. The force nf tbe pul 




OAi.VicsnzATias op thk pneiimogastbics. 



y35 



tlie ubscrvatioBs on a^Hgatofgf it sliows tliat tlie motor nerves 
are not all a&ectL*)! iit the sanje time, Hud tbiit the pneuino- 
g'astrk's resist the ac<.ii_ni mf (his j)eeiili:ir }toif;on after thft 
niuior nerves generally are [►aralyzetl. This s!iuwfl a conser- 
vative provision of'Narare wliieb gaards partioularly the im- 
jjortant influence exerted bj these nen'es upon the heart." 

Our knowledge of the Inherent propertie&of the muscnlar 
fibres of the henrt, and the effects of the pas&nge of blood 
throug-h it* canties, which t<.igether are tuiiipeteiit to keep 
np for a time regular puleatioiiH without the intervention of 
the nervous sy^teui, taken in ccmneetion with the fticts just 
Btuted, concerning the influetiee of aeutlon or galvanization 
of the pneumogastrio nervra, enable uatoeonipreheud pretty 
•well the influence of these nerves on tho heart, T^i^t/ «n- 
d&vhUdir/ pei^ojvji the im/fortani function <f regulating thi 
fores avidfr^'^uency of its pulmtwns. 

Ilardly any reflection is neeessaiT to convince us of the 
importance of sueh a I'liiictioii, and biiw it must of nece^eity 
l>e aeeoinplished throiigli tlie pncumogastriee. It is impor- 
tant, of course, thiit the heart should act at all times with 
nearly the same foree and tre<:jueney. We ha\-e seen that 
the inherent properties of its fibres are competent to make it 
t-oiitmct, and the necessary iuteriiiitterit dilitation of ira cavi- 
ties makes these contractions afisurue a certttio regukritj j 
but the quantity and density of the blood are subject to \iiry 
considerable variations within the liraita of health, which, 
without some regulating influence, would undoubtedly caneo 
variatioua in the hcfirt'& aciionj bo considerable as to be inju- 
rious. This 13 shown by the comparatively inefficient and 
palpitating action of the heart when the pneumogastriea are 
divided. Theae nerves c'L>nvey to the heart a coui^tant influ- 
ence, which we iDfty compare to the insensible tonicity im- 
parted ti» voluntary muscles by the general motor BVfltem. 

' I'ui" iJ^-ibUb oF thesi? esperimenU tlio rwnJer U refeired to bh nrlide by tlie 
■Dllior, oil tliC Affion of IJit Ilrari and Rapiratxaiv^ m Tfm American JoHrnal gf 
Mtdimt HeitnKtt, Ott., IU\. 



234 



a<r<t on allif;;!' 
tliTOWis some ! 
Pesirinn; to '■ 
School of M. 
alligiitor HN 
the lieart cs 
the poison 
coiiiinencc'' 
The pneuii 
tht; eft'fpt ■ 
ol>sei"vati' 
nt first :ii 
woorani 
lint on ]-• 
the iH>i- 
of aflccv 
ness wi' 
this »;; 
The a; 
the h' 
expo;*' 
coiitr: 

pTOIli 

iujer; 

injei 

galv 

ot'tl 

A V 

the 

tioi> 

of ]i 

fecT 



thvt 
mo;; 
mil' 



■ .•»• Ai\e is par- 

-r. they hwoine 

■■■-:;.iut any etVort 

- "•■n-e by a fcH;Me 
.7 .ri'ii-ui'theheart 
_-'-!-ire it still more 

- -he iK'tion of tlie 

■::\n ■•uh^oct whieh 
nru tliniugh the 
::i''n aiul iriviriihii 
.'.ii 11 in whie-li pal- 
■li. There are in- 
r-iij ara'St of the 

- -rher severe iiien- 

- ''V no jneanri un- 
• ■ !!i.':irt re!=nnies it^ 
■:;e iTieiiinuj^aritru'* 
■M!i.'rarily. Wlien 
:ir the heart never 



:/'■ A-:tioii of the 



- I':;-'!! spet'ilily 
■ :':-. the l)Iooil. 
:■.: ;.i'-i ahiiie that 
A-; -'. ;it ill profuse 
■ ■■ -.u'tioii:) of the 

:- -vi'^ on tliL" Iifiirt, 

• ■■ iimririirtyastric* 
<i.«iv:-.L'.;n;;, iiiiil thi 



CACBEffl OF AKBE3T OK THE ACTIOS OF THE nEART. 237 

heart are proprresBivelj cnfueblcd, and, when the loss of blood 
has proceeded to a certain extent, are permanently arrested. 
Cases of transfusion after hiiimorrhage show that when blood 
is introthiced, the heart may be made to resume its pulsa- 
tions. The same result takes j>lace in death by astlieuia ; and 
cases are on record wlicro life has been ]>rolonged,as in hcem- 
orrhaf^o, Iiy transfusion of even a small quantity of healthy 
blood. These facts have Ihhjii demonstrated on the inferior 
animals by experiments already eital. The experiment of 
Ilaller, in which the action of tlie rijrht side of the heart of a 
cat was arrested by emptying it of blood, while the left side, 
which was filled with bhwd, continued to pulsate, ehowed 
that the absence of blood in its cavities is competent of itself 
to arrest the Iioart. Tlie experiments of Erichsen, who par- 
alyzed the heart by ligating the coronary arteries, and Scliitf, 
who produced a local paralysis by ligating the vessel going to 
the right ventricle, shuw that tlie heart may also be arrested 
by cutting off the circulation of blood in its substance, lioth 
of these causes must operate in arrest of the heart's action 
in hrt'iiiorrhage. 

The mechanical cau.ses of arrest of the heart's action are 
of considerable i)athological importance. The heart, in 
common with other nnisclcs, may be paralyzed by sufficient 
mechanical injur}-. A violent blow upon the deltoid paralyzes 
the arm; a severe strain will paralyze the muscles of an 
extremity ; in the same way excessive distention of the cav- 
ities of the heart will jirrest its pulsations. This is sliown by 
arrest of the circulation in asphyxia. Ve have already seen, 
that under these circumstances the heart is inca])able of 
forcing the unaiirated blood through the systemic capillaries; 
it finally becomes enormoutsly straiiioil and distendeil, and 
consequently paralyzed. The same result follows the appli- 
cation of a ligature to tlie aorta. This eft'ect may be pro- 
duced, also, in the cold-blooded animals, in which, if the 
heart be left undisturbed, the pulsations will continue fiir a 

long time. The following experiment illustrating this ponit 
10 



23S 



CmCCLATlON. 



was performed upon the beai't of an alligator six feet in 
Icugtli ; 

TUe animal was poiaouetl with woorara, and twonty-eiglit 
houre after death the lipnrt, which had been exposed and left 
in -nifu, was pulsating reg-iilarly, It was tlien nemyved t'roiTi 
the body, luirj after fiome cxTieritHeDts on the comparative 
force, etc., of tlie piili^atioDs, when 'empty, and wlieu tilled 
with blood, was filled with wuter, the valres having beea 
destroyed so as to allow tree pae&ags nf the fluid through the 
caviliea, and the veasek lij^ated, "The ventriules, stili fillod 
with water confined in tlieir iMivity, were then firmly cum- 
prcti&ed with tlie hand, sci as to subject the muscular fibrea to 
|H)Wcrful compreBaion. From that time the heart entii-ely 
ceased its coutrattiong, and became hard, lite a muscle in a 
etute of cadaveric rigidity^" ' 

Thi3 experiment shows how completely and promptly the 
hatrt, even of a cold-blooded animal, may be arrested in its 
action by mechanical injury. 

Ca&cs of death from distention of the heart are not hjfre- 
quent in i>racticc. It is M-ell established that the form of 
orgiinic discai^e which most frequently IpmU to sudden death 
is that in which the heart is liable to great distention, "We 
reloi* to disease at the aortic orifice. In other lesions, there 
is nut tills teudeU'cy ; but when the aortic onllce is contracted, 
or the valves are insufiicient, any great disturbance of the 
circulation will cause the heart to become cugoi^ed, which h 
lialile tij produce a fatal result. 

Moat perBons are practically familiar with the distreas- 
ing sense of suffocation M^hich frequently follows a blow 
npon the epignstriiiiu. A Tl'w cases are on recoitl of instan- 
taneoua death following a comparatively slight blow in this 
reffliJti. We had an opporlnnicy in the winter of lSoi-'o5 of 
wltncs&iug an autopsy in a caio nf this kind. A young 
mulatto man, employed as a waiter at the Loiii&TiUe Hotel, 
received a blow in the epigastrium^ while frolicking, which 

* ArmrKOn Journal, Oct. 1601, p. SSI 



CAUSES OF AKBKST.OF THE ACTlOK OF THE GEAJrr. 239 



produced iiiBtantuiiieoii* deaths On post-mortera examination 
no lesion vraa discovered. Though these cusea are rare, tbey 
are well kuowu, nnd the etfeets are generally attritiutetl to 
iiijary of the solaf plexus. The distress i& precisely what 
■would occur from sudden arrest of the heart's action ; for it 
is tlie blood charged with oxygen and sent by the heart to 
the system, which suppliea the wants of the tiasiienj and not 
the simple entrance of air into the lungs; and arrest of the 
ciKulation of arterial blood, from any ciiuse, produces suffo- 
cation as completely as tbougb the trachea were lighted. 
This fact is clearly proven by experiments in the article re- 
ferred Co above, it ia a question whc-tbor the arrest of the 
lieart, if tbiB be the pathological condition, be due to concu&- 
sion of the nervous centre, or to the direct eflbctd of the blow 
upon the organ itself. Our present data do not enable us to 
answer thia question detinitelyj but rather incline ub to the 
opinion that in sueh aocidcnla the pymptonia are due todiret-t 
jnjnry of the heart. An additional argnmcnt in favor of this 
view h founded on our knowledge of the mode of operation 
of the sympathetic system. The effects of etimulatiou or 
irritation of thii eyetem are not instantaneouely manifested, 
as is the case in the cerebro'Spinal system, but are developed 
elowly and gradually. 

As far a6 we have been able to learn by experiment, the 
nervous influences which arrest the action of the heart oper- 
ate through the pnenmogastrics. As we have just seen, we 
can closely imitate thiB action by galvanism. The eauscs of 
arrest iu this way are numerous. Among them may ho men- 
tioned, Budden and eevere bodily pain and severe mental 
emotions. With the exceptions of lurest of the heart from 
loss of blood imd t'roin dietentionj from whatever cause it may 
occur, &to])pago of the heart takes place through the nervous 
Bjatetn. It may be temporary, as m syncope, or it may bo 
pcriiiationt ; examples of which, though rare, are sufficientlj 
well antbenticated. 



CHAPTEK TT. 

CIKCri^ttOS OF THE BLOOD Of THE ARTEaiKB. 

I'hjiioliJginU analomjof die aiicries— Conrw of liluod in theRrti?ri«s— -Elufltlrity 
of the a^terlefl^^[^Qt^^:Ul■t; of tlie irterioB — LommotiQu of the ulerjcfl au.! 
Ihro^diLcUaD pf the pnlae— Form of (he polee — Splifgrnognpti — Preann at 
lilooil in Uic art^rli^-— [IiE!iniii3rnuajoiueier — Cai^ipiwlci' — DUTcreDtEftl csr* 
dinwcter — rresBiire iii liiflVri'ii' psrU gf tbt a,rierial trtiuai — lufluirDce of 
rcs|»iration uu llje orteriul iir'SPtiri-— Efftcla of ba-iiwrrhaKe— Rapid i it of th» 
airrciil uf blui>d in tlie urtmL'-if — InstriLmeatt: fur ruvaguHng tlir T«|)idity ol 
tbc arteriul lirculiutioii — Varuitioiie in rapidii> nhti the actioo o( ilit bean 
— R&pldUf iu iliflureuC [HitriB of ibe srcertil ny^ti'in — Aricriil murmun. 



Is nmii and in all aiiimaU possessed of a doulile heart, 
Gacli contnic-tion of tbie or^'-an I'un^ea a diar^e of blood from 
the right ventricle into tliti piilmoimry artery, and from the 
left ventricle into the aorta, "We have seen liow tbe Tnlves 
which guard (Lg orifices of tLcse TL'S&e-Is effectually prevent 
regurgitation duiiiig the intervals of contraction, There ia, 
therefore, but one diitxtion in which the blood can flow in 
obcdieDce to ihia intermittent force; and the fiict that in the 
Bmallest arteries there is an acceleration in the carrent coin- 
cident with each contraction of tlie hesut, which disappears 
■when the action of the Leart ia arPL'sted, shows that the ven- 
tricular syetole is the prime cause of the arterial circulation. 

Thitj part of the physiology of the circulation ia nut ss 
simple as we mi^ht at tir^t be led to suppose. The arteriea 
have the important function of supplying nutritive matter to 
all the tissue, of furnishing to the glands materials out of 



PHY8ICI430TCAI, ANATOMY OF TEE ARTEHTES. 



241 



s-bicU the secretionfl are formed, and in short are tie avenue* 
of supply to every j>art of the orgatiiaru. The anpplj of 
blood rogulates, to a c-onsiderable extent, tlie proccBS of mi- 
tritiun, and has an important bearing on the general and 
epecial ftinctions. The physiological processes necessarily 
demand considerable modifications in the quantity of arterial 
blood wliich is furnished to parts at different tlnie&. For ei- 
smple, during secretion, tie glands require twice or tliree 
times as much blood as in the iiitcrvak of their action. The 
force of the heart, we have eeen, varies but little within the 
limita of health, and the conditions necessary to the proper 
distribntioti of llootl in the economy are regulated almost 
exclusively by the arterial system* Theee vessels are not in- 
ert tubes, but arL': endowed with elafeticitj, by ivbich tlie cir- 
culation is coHsideriibly fscilitated, and with contractility, by 
wbich the supply to any part may be niodilied, indei,>endent- 
ly of the action of tiie heart. Sudden flushes or pallor of the 
countenance are esatnples of the faoilily with which this may 
be ett'ected, It is evident^ therefore, that the propertieB of 
the coats of the arteries ai'o of great physiological importance. 
We shall then comiuciice the etudy of this division of the 
circulatory system with a eonsideriition of its physiological 
auatomj. 



Physiological Anaiom}/ &f thi Arterks, 

The vessels which carry the venous blond to the lungs 
are brnuches of a great tniiik which takes its origin from tlie 
ri^ht ventricle. They do not differ in atnicture from the 
Teasels which cany the blood to the general system, except 
in the fact that their coats are somewhat tiinuer and more dia- 
tensible. The aorta, branches and ramiticationa of which sup- 
ply all parts of the body, is given oft' from the left ventricle. 
Just at the origin, behind the semilunar valves, the aorta hae 
three aaceulated pmiches, catled the sinuses of Talsalva. Be- 
yond this jToint the vessels are cyliudrieal. As we recede 



242 



CmC ELATION. 



firom tlie heart, the arteries "broBcb, divide, ajid siibdi^-tdc, 
until they ai-e reduced to microscopic eize. The Ijnuifliee, 
with the exception of the intercostal arteries, which lonke 
nearly a right angle with the thoracic aorta, are given olf 
ftt an acnte angle. As a rule, the arteries, are nearly 
straight, taking the sliurEeBt course to the parta which they 
supply with blood ; and while the branches progressively di- 
mjriiiih in sizv, hut few are given utt' between the great tiunk 
and the ntiaute veesela which empty into the capillary bvs- 
lem. Haller counted hut twenty bnmches of the raesentei^o 
artery between the aorta and the capillniii^ii of the intctiliiies.' 
So long as a Ycsecl gives off no branches, ita caliber does not 
progresfiively dimiuisli ; as the common ciirotids, which are 
ae la^e at their bit'urcatio'n as they are at tlieir origin. 
There are one or two instances in which vesftcls, though giv- 
ing off numerous brnnchea in their course, do not diminish 
in size for some distance; as the aoria, which is as large at 
the point of division into the iliacs, as it is in the chest; and 
the vertebral arteries, which do not diminish in caliber until 
they enter the foramen magnniu.' Willi these esceptions, lu 
we recede froui the heart, the caliber of the vessels progrea 
fiively diminiahca. 

It has long been remarked that the combined caliber of 
the brflHches of an arterial trunk is much greater than that of 
the main ve&eel ; so that tlic arterial eystem, aa it brauches, 
increiisee in capacity. 

Tiie arrangement of the arteries is ench that the reqiiibite 
Bupply of blood is sent to all parts of the economy by the 
shortest coui-se, and with the leaet expenditure of force frotn 
the heart. Generally the veasela are so eiluated as not to h& 
exposed to pressure and eonaequeut interruption of the cur- 
rent of blood ; but in certain situations, as alwut some of the 
Joints, tbero is necessarily some liability to occasional cum* 

' C\/dop«ditt of Anatomif and Ph^iaiogy, TflJ. i,, p. 220 j Utd H^I'^t^ S!* 
pttuta l'h}itioioffia, tomus L, MC. L, g 1?. 
■ Ibii 



KITStOLOGTOAL ASAlOUY OP THE ARTERIES. 



243 



preaaion. In bome situationa, also, as lu tlte vessels guing to 
the brain, pii.rticiilar]y in Boine inferior aiiimalB, it is rtiiccb- 
sary to moderate the force tif the hlood-L-urrent. on at^cmiut 
of the clcticote structure of tlio organs in which they ara dis- 
trilinte<!l. ITere Nature dihVps a proviiEon Sn tlie shupe of 
anagtoiiioses ; by whit^h, on the one hand, coin^jression tjt' a 
vessel sitnpl;' diverts, and does not arrest the tnrretit of 
b]<>od, and on the other Lund^ the current is rendered more 
eq^nablc- and ihe lurpe uf the heiiil muderiited. 

The arterieg arc provided with lueuibrnnous sheathe, of 
greater or leas fitrength, as tlic veasi-ls are situated iu purtfl 
more or leas expoficd to dislurbiiig; influences pv aceidcuts. 

Kesearches into the minute anatomy of the arteries have 
sbown that tliey are ])ossesscd of three pretty well diiirlted 
coats. As these vnrr very considerably iu arteries uf dificix-nt 
gizea, in their d^cription, it is convenient to divide the ves- 
sels into three classes. 

1, T/ie hry&it arteries f in which are included all that aro 
larger than the earolide and common Iliiiea. 

2, T/i(} arteries of mvtiium stse ; that la, between the 
carotids and iliti<% rtud the bniidlciit. 

3, The itmailmt urterfes; or those less than ^^ to -^, o\' nn 
inch ill diauifter.' 

The largest arteries are endowed with great strength and 
etastleity. Tlieir external coat is coinpi>sed of white or in- 
elastic fibroua ti:^sue. Accordins to KoHitor, this coal \a uo 
thii-Iior iu the largest veasetsi than in some of the vessels of 
metlimn size. In eonie medium-sized vessels it ie aftuully 
thicker than iu the aorta. This is the ouly coat which ifi 
vaseular. 

The tuiddle coat, on which the thickness of the vessel de- 

' Thii fa eMonllally ite divi^on jnsde l>j KiHUk*r {Manval of Humat Afirro- 
Kopiu AHoioaiy, Loudon, ISfiu, p. 485). Some aiiuioinUta make Siva or evta 
moire cokU to the ulcricB. 1'Iil- ihit-c c^uis arfi pruti^ well markud, each p06- 
■euing Ji^^iini'tive properties. The D'umcroua ouitia whifli are BomeCimoa giicu 
UG, nun; III' Ibtm^ bjuijI^ l^jcrs of tbe sume tJB8ue> Tbc divieiau inlo IUti.-c c.-(Jtttf 
Is more simple mi pbyaiu logical. 



244 



CntCCLATION. 



pendfi, ia compoBed phiefly of the yflfow clnstic tissue. Tbie 
tissue is disiioscd in uumeroiis laytrs. First ■we have a thin 
layer of ramifying elastic fibres, and then a niiniber of layer* 
of duAtiL' membrane, with mimercius uval lungididinal opeo- 
ings, "wliieh line given it the name of tho "fenestrated riieiii- 
brane." According to Kiilliker, between the layere of this 
naenibrane nre found a few iinstriped or involuntary muscu- 
lar tihrua ; and Ruhiii statee that they exist in layers only in 
the avterioft of medium size and the smiill artcriee.' Miisfu- 
lar fibres, if they exist at all in the largest arteries, are very 
few, and of little phygiolowica] importance. Tlie middle 
toflt of tlie jjirgest arteries gives thonv their yellowish hu«j 
and tlte elasticity for which they arc so remarkable. 

The intenial coat of the largest arteries does not tlifier 
materially from tlie lining momlirane of the rest of the 
srterial system. It ia identical in structure with the endo- 
cardinin, tlio mcnibnine lining tho cavitiL's of the heart, and 
is continued throu^li the entire vapcrular Bystem. It h a thin 
liotnogencous membrane, covered with a layer of elongated 
epithelial ei-ales, wirli ovtd nuclei, 'their long diameter fol- 
lowing tlie direction of the vessel. 

The arteriea of medium size posaeaa considerable etrength, 
Bome elasticity, and very grost contractility. In the outer 
and inner eoata we do not distiugutsli aiiy great difference 
between them and the largest urteries, even iu tlilcknc^. 
The emential dili'erouce in the anatomy of tliese vessels ia 
found in the middle coat. Here we have a continuation of 
the elastic elements found in tlie largest, vessels^ but rela^ 
lively dimicishL'd in thickness^ and mingled with the tii*i form 
involuntary muscular fibres, arranged at right anglos to the 
couiise of the vessel. These Jibres are found in the inner 
layers of the middle coat, and, according to Robin, only in 
arteries bmallcr ttiftu tln> carotids and primitive iliaes. In 
arteries of medium size, lite tho femoral, profunda femoris, 
radialj or ulnar, they exist in numei-ous layera. There h no 

> LiTTEfi R KoRiK, DicHonnaire dt iiidttitui, Ptrip, 1878 ; Article, Ar^rt. 



PSTSIOLOaiGAT, ASATOMT OF THE ABTEaiEa. 345 

distitict divUion, as regarda tlie middle coat, between tlie 
largest arteries and those of medlam Bixe. Ae we recede from 
tbe heart, muscular fibrcB {gradually miike tlieir apijearauce 
between the elastic layers, progresBively mcreeiaing in quan- 
tity, wliite tlie elastic elpiiieiit ia diniinitiliefK 

In tlic Bmsillest arteries (lie exterrml coat h tliio, and dis- 
appears just Ixjtbre the vessels empfy into llie capillary sys- 
ti'ui ; BO tliat tlie xery gmalleAt arterioles have only the inner 
coat and a IiLj-er of muscular fibres. 

The middle coat ie com^x^ed of circular mnecular Sbres, 
xritbout a.[(y ndnnxture of elastic elements. In vessels yhs 
of an inch iu diumeter, we Uave two or tliree layers of fibres; 
bat as we near llie capillarifffi, and aa tUo vessels luso the ex- 
ternal fibrous L'oat, these fibres have hut a sin<^le layer." 

Tlio internal coat presents no ditTercnt'e from tbe coat in 
other veflsels, with the exception that the epithelium is leas 
diatintrtly marked, and is Ktat near the capillnries; the mem- 
brane being Btmlded with longitudinal ova! nuclei, 

A tolerably rich plexus of vesaeU is found in the exlemal 
coats of the arteriee, Tbe&e are called the vasa vuforum, and 
come frum the adjacent arterioles, havinj; no direct cunnee- 
tion with tlie vessel on which they are distributed, A few 
ve^^iels ]H!netrato the external hiyera of the middle coat, but 
none are ever found in the internal coat. 

Nervous filamentti, principally from t!ie sympathetic sys- 
tem, accompany the arteries, iu all priibability, to their re- 
motest ramifications; though they have not yet been denion- 
Btrated iu tlie smallest arteriolea. These ai*e not distributed 
ui the wuUh of the large vessels, but rather fullow them In 
thuir course; their tilaraeutd of distribution being found in 
tho&o vesr^ds iu which the nmsculaj element of tbe middle 
coat predorainatBB. When we come to treat of the phyaiology 
of the organic aystom of oervea, we shall see that the " vaao- 

* The Btrucliire of the smallest iirterios can 1w beaMCiFtillj- cihitiited io fresh 
inl<:T0Aco{iIc prof br&tioDii of the pia muter, in which Ibc Tuious poinu M wliidi 
«e bivc aUuded eta bt dtaHj stadied. 



24C 



OIHCCXATION. 



motor" nerves pl&j sn important part in regulating tlie 
function of uutritiou. 



Course of tlie Blood hi the ArleHea^ — At every pnlsatiun 
of tLe lienrt, nil tlie lilooi] funtainerl in the ventricles, exc^jrt- 
ing^ perliapn, a lew ilrops, is forced into tte great vegficli-. 
We hare already studied the valmilar arrangeTnent by wkicli 
the blood, once forced into these vessels, ig prevented from 
returning itito the ventmlea during tlie diastole. The sketch 
we have giyeo of the anatoinj of the arteries has prepared ua 
for H eoriiplfxity of plienomena in the circulation in thege 
Te8BeI&, n'liith would not obtHJn if they "wero einijile, inelastic 
lubes. In this ease the intorinittent force of the Iieart would 
be felt equally In nil the ve*+el9, and tiie arferljLl cireiilation 
would be snbject to no ninditiciitioiis which did not come 
from the action of the central organ. Ah it is, the blood is 
received from the heart Jntiii vessels endowed, not only with 
great ehistiuity^ but with conlraclility. The elasticity, which 
is the prominent property of the largest arteriee, moderates 
the iutormitteney of tbe heart's action, providing a continuoua 
supply to the parte; while the contractility of the BraalU'St 
arteries is capable of increasing or diDiinishing tlie supply in 
any jtarE, aa may be required iu the various funetiona. 

EJanticHy of the Arierm. — This property, partien!m-Iy 
marked in large ves&elu, lias long been recognized. If,, for 
example, we forcibly distend the aorta with water, it may be 
dilated to more than double its ordinary capacity, and will 
I'esumc its original size and form as soon aa the pre&sure ia 
removed. Thie sinijile experiment teaches ub, that if the 
lorce of tho he;irt be Hiitticlent to distend the ^Tcat vessels, 
their elasticity during the intervals of its action must be 
continually forcing the blix)d toward tho peripbei-v. Tlie 
fatt that the arteries are distended at each syutL'le is abun- 
dantly proven by actual experiment; though the immense 
capacity of the arterial system, compared with the ^mall 



ELABTICITY OF THK ABTEEIE8. 



347 



charge of bl>oJ irbioh enters at each pulsation, renders tht 
actufti liistciition of the vosaek lees than we ehouM be led to 
expect from the force of the IjeMrt^s fontractioa. Tlie most 
satisfactwry experiments on tbia subject are those of Poiseu- 
ilk'.' This observer illustmtt^d the WilntRtion of the arterica 
in the tbilowing way ; Hrtving exposed a coiiaideraUIe extent 
of the primitive ciirotid iu a horse, he enclosed a jwrtion in a 
tin tube tilled with water and coimectoil with a small upright 
graduated tuho of glass. The oponiiign nmund the artery, as 
it pa^ed in and out of the apparatus, heiiifj carefully sealed 
with talloiv, it is evident tliflt Jinv dihitaHoti of the vessel 
Would be indicated by an elevation of the water in tlie grad- 
nated tube. This esptrimeat invariably ehowed a marked 
dilatation of the artery with each contraetion of the heart. 

" We remark that the dilatation is not very eonsidoraljle ; 
thua it is not easy to recognize it by simple inspection, in an 
artery of even the callbep of that wbleh occupies us, after we 
have it exposed,"* 

It being fully established that the arteries are dilated with 
each ventricular systole, it becomes inipovtant to study the 
influence of their elasticity upon the current of blood. Divi- 
sion of an ai'tery in a living aniinal exhibits one of the ini' 
portniit phenomena due to the elastic and yielding character 
of its walls. We observe, even in vessels of considerable 
size, as the carotid or femoraJ, that the flow of blood is not 
intermittent, but remittent. With each ventricular systole 
there is a sudden arid nmrked impulse ; but during the inter- 
vals of contraction, the blood continues to flow with consid- 
erable force. As we recede from the heart, the impulse 
becomes less aud less inarkfid ; hut it is not entirely lost, even 
in the einallest vessels, the flow becoming constant only in 
the capillary system. That the force of the heart is abso- 
lately intermittent, is showii by the fullowing experiment: 

' PoiHKriLLi;, lUehrrtJir* ««r rAcJion Ja Ariim tlana la Circu-latiott jlr/i 
nelk.^-J'jHmcl J' I'liysii^offif, PariB, 1825, tome ix,, p, 44, 
• Ibid., p. 48. 



343 



CIHCCLATIOS. 



If the ur^ati be expoewl in a living animal, aud a canulR be 
intruducetl tlirutigli the walk into cue of the "ventricles, wc 
have a powerful jet at each sjrstole, but qo Moot] is discUurgeU 
duriuf; the diastole^ The sjiuib absolute iuteiinittencj' of tlie 
current wlU be eeea if the aorta be divided. It is evident 
that we mudt look to the arteries thenieelvea for the force 
which produces a flow of bljod in the intervals of the heart's 
action. The cuiivefsion iif the intermittetit current in tho 
largest vessuls iuto a nearly constant liow in thie &malleeit 
arterioles ia efieeted by tiie physical property of ehis- 
tielty. This may ho illufitrated in any elastic tube of 
sufficient k'ugtli. If we eouuect with a syringe a series of 
rubber tuhea progressively diininishiog in ealiber, and dia- 
dmrging by ft very fliim!! orifice, and inject water in an iu- 
termitteut current, it' the appai-attw be propyrly adjusted, 
the liuid will be discharged at ttie end of the tube in & 
continuous stream. Kuarer the syringe, the stream will 
be remittent ; and directly at the poiut of connection of 
tlie ejriuge with the tul>e, the stream will be iutennitteiit. 
The intermittent impulse may be said, in this case, t<i bo 
proi^resaively absorbed by the elastic walls of the tube. Each 
impulse first distends that portion of the tube nearest to it, 
and farther on, the distention is diminished, until it become* 
inappreciable. If tlie syringe be connected with two tubes, 
one elastic and the other inelastic, the cmTciit will be either 
remitteat or contiunous in the one, and intermittent in the 
other. 

This moditicfltion of the iiuiiulae of the heart has great 
physiological importance; for it is evidently essential that 
the current of blojd, as it flows into the delicate cBpillary 
vrasek, aboiild not be alternntely iiUerniitted arid impellod, 
with tlio fiill pQwer of tlie veutricle. Alter all, it is in the 
capillaries that the blood pertbrnis iu functions, and here we 
should iiave a constant supply of the lluid in proper quantity 
and in proper condition to meet the nutritive requirementF 
af the parts. 



ELASncnr of the AKT£iICI£8. 



249 



Tlie elastifitv of tlie arteries favors the flow of the bioyd 
toward tlio capillaries ]>y a mecliflnism wliich ie easily xm- 
dcrslood. Tlie blood discharged from the heart dictuuds the 
elaatic vessel, which reacts, alter the distending force ceaeee 
to operate, and compresses its fluid contents, Thia reaetioii 
would have a tendency to force the blood in two directions, 
WCTe It not for an iMtftntftneoiis closure of the valves, which 
makes regiirgitation impossible. The influence then can only 
be excrleil in the diretrliou of the perijjhery ; and, if we uau 
iiits^inG us divided an action whii;h ie propagated with eucli 
rapidity, the rca{:tion of that portion of the vessel immedi- 
Htfly distended by the heart, Jifitenda a portion farther on, 
whjeh in. its turn distends anonher portion, and so the wave 
pafiscs along until the blood is discharged into the capillanes. 
In this way wg can see that in vessels removed a eufficient 
distance iroin the heart, the force esoHed on the blood by 
the reaction of the elastic walls is competent to produce a 
very considerable current during the intervals of the heart's 
contraction, 

This theoretical view is fully carried out by the following 
Rimple and conclusive experiment of M. Marey. He con- 
nected two tubes of equal size, one of rubber and the other 
cf glass, with the stop-cock of a large vase filled with water. 
The elastic tube was providei.1 with a valve near the stop- 
cock, which i)revented tlie reflux of fluid, and both were 
fitted with tijia of equal caliber. When, by alternately opening 
and closing the Btop-cock, water was allowed to flow into theee 
tubffi iu an intermittent stream, it was found that a greater 
quantity was discharged by the elastic tube ; but an equal 
quantity was diaeliarged by both tubes when the stop-cock 
was lel\ open, and the fluid allowed to pass in a coutinuoua 
Btrcam,' 

This Biinple experitncnt shows that not only does the elas- 
ticity of the arteries convert the intermittent current in the 
largest vessels into a current more and more nearly contin- 

> Ma.REy, Circultrtion du Sang^ Farie, 1809, pp. 1S8, 131. 



if 50 



CIECDLATIOjr. 



nous k& we approacli fLe peripliery, but that wlien reflux ia 
prevented, as it is by tbe seiiiilmuir Talvee, tJie reellieDcy of 
tlie arteries asaiats the circiilatiou. 

CGntrairtility of ihs Arteries. — It ia a ftiUj eetaliHahed 
anatomical fact that the medium -sized and smnllesi lu'teries 
<tniitrtin Ci^ntractile or muscular elenipnts; and it is al&« u 
fact, pcuveu by actual exjwrimentj that as a consequence of 
the condition of these fibres, tbe vessels undci^o i-on^id^rabk 
TariatioD in tbelr calibei*. The oiHiiiuna of tbe older jihyei- 
ologista on this rjaestiun hare oulj au bii^torieal interest, and 
will not, therefore, be discuBBed. Among the more recent 
invcfitigations on this Bubjeet, we have tlie t'xperimcnta of CI. 
Bernard and Sebiff, which have bi;en repeatcdlj cunhriiied, 
Bhowing that thrungb tbe nervoua system tbe miiscubir coats 
of arteries may be readily made to contract or bcL-oine re- 
laxed. If the sympathetic be divided in the neck of a rab- 
bit, in ft very few minutes the arteries of the ear on that eide 
are notably dilated. li' the divitled extremity of the nerve 
be feebly galvanizedj the vessels soon take on contraction, and 
may become smalh^r than, on the ojijiotite side. These expe- 
riments demonistrate, in the most c».niclnsive manner, the con^ 
traetilo properties of the email arteries, and give ns aii idea 
how the supply of blood to any pnitlcular part may l>e re}?u- 
lated. The vessels may he most eftecftially excited ihr^mgh 
the nervous system ; and it is on account of tlie difficulty in 
produRin^' mai'ked results by direct irritation, tiiat the older 
pbysiologieta were divided on the Bubject of their *' irrita- 
bility." 

The contractility of tlie arteries has great physiologieal 
importance. As their function is simply to supply blood to 
the various tissues and org-ans, it is evident that when the 
vessels going to any particular part are dilated, the BUppljr 
of blood is necessarily increased. This is particularly impor- 
tant in the glands, which, during tlie intervals of secretion, 
receive a comparatively small quantity of blood. Bernard 




oojiTBACTiLrn: of the aktekfes. 



251 



baa showti, by a beautittil e.prii?s of experiment ■wliitih will 
be more particniarlj alladed to on the snbjeet of secretion, 
that galvanization of wbat be calls tbe motor nerve of a 
gland dilat&s the vessels, largely increases the 6ttpp]y of blood, 
and induces eecretion ; wLile gaU'ariizatiou of the sympathetio 
tilaraents contracts the Tessclp, diminislieB the supply of bluod, 
and arreets secretion. The pallor of parts exposed to cold, 
and the flush produced by hait, are due, ou the oue hand, to 
contracticm, and on the other to dilatation of the eniall arter- 
ies. Pallor and blushing from mental emotions are examples 
of the same kind of action. 

The ulterior eH'ects on nntrition, which result from dila- 
tation of tJie vesaels of a part, are of great interest. When the 
supiily of blood 18 much increased, as in Beetion of the 
Bympathetie in tlie neck, nutrition is exaggerattd, and the 
temperature is raised beyond that of the retit of tlie body. 

The idea, wliieh at one time obtained, that the arteries 
were the seat of rhytlimieal contractions, which had a faTor^ 
able irilluenee on the current of blood, is entirely etrouoyas.' 
It is hardly necessary trj repeat that the prime cause of 
the artL'rifil clri^ulation ia the force of the ventriclea. We 
bare seen tJiat the elasticity of the arteries produces a flow 
daring the intervals of the hearths action, and the qnestion 
now ariaes wlicther the force thus exerted is simply n re- 
turn of the force required to esiiand the vcssek, which has 
been borrowed, as it were, from the heart, or ta sonictbliig 
Bupcriidded to the force of the bofirt. The exjierimcnt of 
Marey, already alluded to, settles this question, AVlien 
water WHS forwd in an intermittent current into two tubes. 
one elastic and the otiier inelastic, but dischai-^Nng by open- 
ings of equal sixe, by far tlie greater quantity was discharged 
by the elastic tabe. A little reflection will show how the 



•■Sctiff bia notioeil rhythmkiil eontructioaa in ibo anper6eiftl arteries &r the 

eat in tlie rnTibU, ivii*! witQe otber uaiinnb ; but tliia plienoroenon IB PXee^ 

^onol, and tbo moreni'VDta do not &pp«iu la fuvOr tliu ciirri>nl of blood. 
tMjL3«-EoTrjmiig, Phifiiolngu tome, iv., p. "IT.) 



£53 



CmCCLATlON. 



action cif tlie elastic arteries mtiat aetiiallj assist tte t-ircnU* 
tton. The reaniencj of the vessels is continually pres^irij^ their 
contents toward the periphery, as regurgitBtlon is rendere*] 
impOBSii>le hy the action of the semilutiar valvra. Tlie dila- 
tatJon of the vessels with each svetoloj of course^ admits an 
inereased quantity of blood ; aofl it has been experiraentallj 
demonstrated, that the same iutennittent force exerted oi 
au inelastic tuhe, will discharge a leas quantity of liqaif 
from openinga of equal caliber. 

Snperadded, then, to the direct action of the heart, we 
must recQijinzp, as a cause inHutncing the flow of blood iu 
the arteries, the resiliency of the veesfls, especiftUy those of 
large size, this force being derived origiuully from tlie heart. 

Thus it ivill be seen that the arteries are constantly kept 
distended with blnod hy the heart, and by virtue of their 
elasticity and the progressive increase in the capacity of thi^| 
syetem as they branch, the powerful contract ions of the (Cen- 
tral organ only sei-ve to ke*p up an equable current in the 
capiUarica. Ttie Binall vessels, by virtue o^ their contractile 
walls, regulate the distribution of the blood ; acting as tin 
guards or eeutiuela of the process of nutritionj and, in fact 
all the numerous functions in which the blood is coneumi 
Obeying the commands transmitted through the pympathctio' 
nervuns system, (hey allow (lie passage to every part of th( 
proper quantitj* of the nutritive fluid at the proper time. 



Locomotion of tf*4 ArUHi^s and Produdlwi of thi Pt^se.- 
At each contraction of the heart, the arteries are increiised 
lenj^tli, and iniiuy of them undergo a considerable locorao- 
tion. This may be readily observed in ves^sela which are 
tortuous in their coui'&e, and is frequently very marked in the 
temporal artery in old persous. The elongation may also ItOjH 
Been if wc watch atientirely the point where an artery biftir*^' 
cato^, a-^ at the division of the common carotid. It is simply 
the meclianical effect of audden distention ; which, while i| 



pBODCcrnns of thb pdise. 



95S 



I 



mcreflsea the caliber of the veaBclj causes an uloiigation 
even more nmrlced. 

The finger plat'eJ over an exposed artery, or one whicli 
3ies near the surface, experiences a sensation at e^^ery beat 
of the hetirt, as though the vessel were striking agalnet it. 
This baa long been ol'served, and is called the pulee. Ordi- 
narily it is Bi)]>rec-iated when the current of blood can l»e 
enbjef,ted to a certain amount of obstruction, as in tlie nidial, 
"whieb can readily be compre^ed arcainst the bone. lu an 
artery imbedded in eoft p&rts^ which yield to preaeiire, the 
a.ctual dihitation of tlie vessel being very slight, pulsation i? 
f^\t with dilHcuIty, if at all. When ohstrLiction is eomplet-e, 
a^ in ligation of a vessel, the pulsation aho^-e the point of 
1 isatiirt) is, very marked, and can be readily appreciated by 
tXie eye. The explanation of this exaggeration of the uiove" 
Cftient ifl the fullowJiig: Normally, the blood passes freely 
tliroiigb Ibe arteries, and prodncjcB, in tlie siualler vessels, 
■^ery little nioveiiient or dilatation ; but when the current is 
obstructed, as by ligatious or even compression with the 
linger, the force of tlie heart is not &cnt through the vessel to 
"the periphery, but is arrested, and therefore becomes more 
tuarked and easily appreciated. In vessels which have be- 
c::u>me undilatable and inoontpressibic from calcareous deposit, 
the pulse cannot be felt. The character of the pulse in- 
^liuatee, to a certain extent, the condition of the heart and 
"vefisela. We have &pokeu, when treating of the heart, of 
the varying rapidity of the pulse, as it is a record of the 
rapidity of the action of this organ; but it remains for us 
to consider tlj^ mec^banism of its production, and its various 
characters. 

Under ordinary circumstances, the pulse may be felt in 
all artericB which are exposed to investigation ; and as it is 
due to the movement of the blood in the vrasels, the prime 
cause of ita production is the contraction of the left ventricle. 
The lato very interesting ex^>erime^ts of M. Marey hare 
shown that the impulse given to tiie btood by the heart ia 
17 



25* 



CIKCIJIJITTOS. 



Dot felt in all the vessck at the Batue inetant. By ingeniutia 
contrivances, wliicli will be dL'scribed farther on, this observer 
hue Bucceeded ia registerlag simultaneonsly the impulse of 
the Jieart, the pulse of the aorta, and the pulse of the femoriU 
art^rv. He has thus ascertflioed tbut the contraction of the 
ventricle its anterior to the pulsation of the aorta, and th* 
pukatiun of the aorta precedes the pulse in the femoral.' 
Tin's onlv eonlirnis the Tiews of other phygiologtBts. particn- 
iarly Wuber, who described this progressive retardation of 
the pulae ae we recede from the heart, estimating the difier- 
criL^e between the ventricular eyetole and the puleatton of the 
artery in the foot, at one-seventh of a second,* The observa- 
tions of M. Marey are particularly referred to as being the 
most cotioluelve. 

It is evident from what we know of the variations, which 
occur in the force of the heart's action, the q^uantity of blood 
in the vessels, and from the change which niny take place in 
the caliber of the arteries, that the character of the pulse 
must be Gubject to numerous variations. JUany of tbeae may 
be a[hpreciated siniply by the aeuBe of touch. We find wri- 
terB treating of the 60t\ and compressible pulee, the hard 
pulse, the wiry pulse, the thi-eady pulse, etc., as indicating 
various conditions of the circulatory system. Tlie character 
of the pulse, aside fi-om it^ frequency, haa always been re- 
garded a^ of great importance in disease ; and the variations 
which octur in henlth form a moet interesting subject for 
physiological inquiry, 

M>rm of the Pulse. — It ia evident that fe^ of the charao. 
ters of a puUatlon, occupying as it does but a seveutieth 
part of a minute, can be a^ertained by the sense of toudi 



' M^REr, Cireaiation da Sanff^ p. 197. In an inicle publiBhoii in the 
Ji>iitTml de la PhgtiotogU, 1B06, Umx li., p. 267, Muruy took ground ogaiiwl 
llie progressive rptorilatiou of tbu pulse in arterifo letiioved from (he hvnn ; Iw) 
in \iM liiriL work tbc fact is ailniiU«(l, and Mwma provpn beYDail ■ doubt, 

' Melxe-Edwahdb, /Ay«fofej/««, lome It., p, lS>a, 



FOEM OF THB PTTTJR, 



Sof 



alone. This fact haa been appreciated by physiologists ; and 
"nntlnn the last few years, in order to accurately study this 
important subject, instrumente for registei-ing tbe impiilHo 
felt by the arterial system bave been constructed, to enable 
TI9 to accurately anslyze t!ie dilatation or niovenienta ot" the 
veg^ls. The iJea of awcU an instrament was probably sug- 
gested by the fbllowing sinjple observation : When the legs 
are cros«eil, with one knee over the other, the beating of the 
pupltteiil artery ^vill produce a marked movement in the foot. 
If we could apply to an arter}' a lever pro^-ided with a uiarlt- 
inf,' point in contact with n slip of paper moving at a detinite 
rate, this point would register the niovementB of the vessel, 
and its changes in csdiber. The firet pliysiologiat who put 
thU in practice was Vierordt, who constructed quite a com- 
plex instrument, so arranged tliat the impulse from an aci^es- 
Bible artery, like the radial, was conveyed to a lever, wdiieh 
marked the movement upon a revolving cylinder of paper. 
This iuetnimeiit woa called a '"ephygmograph." Tlie ti-acea 
made by it were perfectly regular, and eimply marked tlie 
extremes of dilatation^ esaggeraterl, of course, by the length 
of the lever, and the number of pulsations in a given time. 
The latter can, of course, be ejisily estimated by more simple 
means ; and as the former did not convey any very definite 
physiological idea, the apparatus was regarded rather as a 
curiosity than an instrument for accurate research. 

The principle on which the instrument of Vierordt was 
constructed was correct, and it only remained to construct 
one which would be easy of application, and produce a 
trace representing the shades of dilatatiun and contraction 
of the vessels, in order to lead to important practical results. 
These indispeii&able conditions are fully realized in the 
q^bygmogrflgb of M. Mai-ey, to whose researches on the cii^ 
culation we have repeatedly referred. The in&trument sim- 
ply amplifies the changes in the caliber of the vessel, without 
deforming them ; and though its application is, perhaps, not bo 
easy as to make it generally uaeinl in practice, in tlie bauds 



256 



dKCULATIOIT. 



of Marey it has ^iven us a dofinite knowledge of the physirt- 
J'U;,'icaI character of the pulse, and its nioditicatious iu certaiaj 



Ha. 8. 



SphjBrnoK-niph ur Marcy. Tiie ip|iartitn« U sroarelj liiil onllm ftimim, rnihat lbs 
Kvnna nri'lnr ihe wr^w V I* iHrvclly ever Chw i»(1ibI •rwrj. Tiic mflvi'inpm* of the 
piilwi nn.' trniitniUtoi:! to tbf loni:; mill l]s\\l WL*od(<n kiv.i-r L. Dud n-i^la'tcTivl viKni (b« 
inrrnrr> P, u hMi i<! uiut'pil B[ ■ Unawii nte tty (hi- Flock-ivurk 19. Thi' ii|i]inniiu» U f-a 
*dlQ»lirf tliut thp inuri-rnptitti of lUf Te»*d *re ftti'iinitrlj ftinlillBeil anJ ifjil^lrrrd lij 
Chi> ^iirsTup p^iLnl of Uis iBvii-r. fM.&mKT., RtciieFeiUf, etc.^-Jwimal de la ji>iurtiiivgl4, 
PaH«, laOJ, touD m., p, »4.| 

di^ascs ; mrnnuatiou which is exceedingly desirable, aodfl 
cuuld nut be arrived at by other meaus ot iiivefiti^atiou. In 
Bhort-^ its mechanistii is so ociinrate that, when skilfully used,, 
it gives on paper the actual "form of the pui-ae.* 



Ttii. C 



n>M of Vkrantl. l,IUd.> 



This inBtrnmeiit, applied to the radial artery, gives a 
trace very difterent from that ohtaiaed by Vierordt* which 



FOEST OF THE PCUE. 



257 



vaa simply a series of regular elevatfous nnil (lepreseione. 
A comparison of the traces obtained liy these two ubservera 
j^ves an idea of the defects which have been remedied by 
Morey ; for it is evident that the dilatation and eontractiou of 



Fto. B, 




Tntx of Mac*]', rtstloaa of funr trwoi taksa In dJIIbnnil coDillLloni of the pulse (fbCl.) 

-rfjje arteries cannot be as regular and sirnjile as wnuld be in^ 
^erred merely from the trace made hy the instrument of 
"^^ierordt. 

Analysing the traces of Marey, we eeo that there U a 

<3 J I atatioQ following the eyatole of the heart, marked by an 

^l^^ration of the lever, more or lesa Badden, as inilieated by 

tTm^ angle of the trace, and nf g;reateror leesaniplitude. The 

<i i 1 sBtution, having arrived at its maximnm, is followed by 

oo »^tractioa ; wliich may be slow and reji:uhir, or may be, and 

ge-x:»erally is, intemipted by a second and slighter upwanl 

movement of the lever. This fteeond impulie varfes very 

mi-K-li in ami'litnde. In eome rare itiBtatices it is nearly m 

tnefc^rked as the tirst, and may be a]>preciated by the linger, 

gi^"ing the aenaation of a double pulae followiiif;; eath con- 

ir**<5tion of the heart. This ia called the dicrotw jiulfie. 

A& a rule, tlie first dilatation of tfio vessel is sudden, and 
Wc3icated by an almost vertical line; this is followed by a 
t.loi^- reliction, indicated by a j^radual deaceut of the traee, 
wliith is not, however, abftolutely regular, but marked by a 
fih^lii elevation indicating » second impulse. 

Tlie aitjphtude of the trace, or the diAtatice between the 

ii'gliest and lowest points marked by the lever, depends upon 

til's atiioaDt of constant tension of the veesels. Marey has 

U>UTiii that the amplitude is in an inverse ratio to the tension ; 

v;iu»;li ja very ea&ily understood, tbr whun the arteries are little 

diAt^ncled, the force of the heart must be more marked in ita 



CTECrtATIOS'. 

eifecta tliau wlieu the [.■rcijBUi'e ol" bJood in them is very preat. 
Any circumstance wliich fiicilitates the flow of MikmI from 
the arteric'S into the cnpillaries will, oJ' course, relieve the 
teusioQ of the mieriiil svstera, lessen the obstacle to the force 
of the heart, and inoreaee the amplitude of the puUation ; 
Bn<l vt'oe versa. In support of this view, Mafey h&£ fonud 
that cold applied to the eurfoee of the Lodj, contracting, as 
it does, the eiiialleBt artej-ies, increases the arterial teneion 
and dipiinisliea tlie auiplitudo of the pulsation ; -while a mod- 
erate elevation of temperature producea an opposite effect. 

la nearly all the traces given by Marey, the desceat of 
the lever indicatee more or less occillation of the mass of Llood. 
The physical properttea of the hiri^er arteries render this 
iDevitahls. As they yield to the distending influence of the 
heart, reaction occurs after this force U taken off, and, if the 
difetentioti he very great, give* a second impulse to the blood. 
This is quite markedj unless the tenfiion of the arterial ayeteiii 
be so great as to offer too much re&tstence. One of the most 
favorable conditions for the manifestation of dierotism ia 
diminished tension, which ia always found coesiBtiDg with a 
very marked exhibition of this phenomenon. 

The delicate ioatniment employed by Marey enabled hira 
to accui'ately determine and i-eji^ister these various phenomena, 
by observfttioufi on arteries of the human subject and animals ; 
and by meana of an ingeniously constructed ** w/icmo," rep- 
resenting the arterial eyeteniby elastic tubes, and the left ven- 
triele by an elastic bag, provided with valves, acting as a syr- 
inge, he satisfactorily eatablished the conditions of tenBion, 
etc., necessary to their production. In this scfi.ei}ia-^ the regis- 
tering apparatus, simpler in conBtruetion thnu the tphygnuf- 
graph, could be applied to the tubes with more accuracy 
and es^. 

He deniouetrated, by experiments with this syslem of 
lubes, that the amplitude of the ptUsatione, the force of llie 
central organ being tho aame, ie greatest when the tubes nro 
moderately distended, or the tendon of ^uid is low, and vie* 




lOBM or THE PC 



^59 



r«r«a. He demongtrated, also, that a low tension favors 
dicrotism. In this latter observation he diminislied tlie ten- 
eioa bj enlarging tlie orifices by which the fluid i& diichar^eJ 
from the tubes, iiuitatiog the dilatation of the &mall vessels, 
by which Uie t-ensiou is diminiehed in the arterial ^stem. 
He also demonstrated that an important and esscntiiil element 
in the production of dicrotism, is the tendency to oscillation 
of the liuid in the vessels, between the contractions of the 
heart. This can only occur in fluid which has a certjun 
weight, and acquiree a velocity {rom the impulse; for 
when air was introduced into tlie apparatus, dicrotism coiild 
uot be produced under any cJrt^uni&tanoeB, aa the fluid did 
not possess weight enough to oscillate between the impulses. 
Water produced a well-uiarked dicrotic impulse under favor- 
able circnmBtances; and with ujercury, the oseillationa made 
two, three, or more distinct impulses. 

By these experiments he proved that the blood oscillates 
in the vessels, if this luuvoment be not suppressed by too great 
pressure, or teneion. This oscillation gives the 6ucces*ive 
rebounds that are marked in the descending line of the 
pulse, and is capable, in some rare instances, when the arte- 
rial tension ie very slight, of producing a second rebound of 
Bofficient force to he appreciated by the fln^r/ 



' In treating of tbe fcrm of Oie pulse, of course Including tjicratiflm, from a 
pnr^ly phyHiologimt point of view, it« bare given an anBlyais of the phycioloirical 
poniou of the Iftte wurb uf M^hkt [Phi/muhjie 3lidita!s dt la Oireulatian du 
Saiiff, Piris, 18US). To poHidtifi of thb wurk rdaliiig 'o llie uciJon of Ciic henrt, 
fiaucdB, vie, we boVo alrenJy rcftrred. Aa is evidfiit fi"oni ftur fikctcSi of ibis 
iOJitLntnicntH tor regk(«ritij; tlie |jul»e, the author ref«m-d lo is die on1;r onv who 
\u» pToducoI a trace correctlr reorei^enitiDg the shadt's of locomotion atiiL liitatjitjoD 
of the artniva; and by las btillioijt and rngmuousi experinientH, which cannot be 
too highly prais^ he baa wtl!^ many iniportatit points, and j^rea a prMrioua 
lueftns^ of inTCstigBlioi W other pliysiokglBts, H<: Iirs opened a now field lor 
eludy of the pathological changes ia thu form of th*" jmlse; but bpfore ire 
cait advnsra far in this direction, y/if vmiM bocomc furuillar witli all the mmli- 
flefetfmu wliich occur lu hralcb, ati end which aa yut is bj no mcanB fiilly attaineii 
Tbt MioaWictioti of ■ epbygrioprajih naa a prablcm of great ddicacy, nuii s 
aertun nnitmBt of procilcul eip«rirQce «ith the ibsIrumtMit has counted ud uf 



2G0 



CiBClTIAtlO^'. 



Without treating of the varijitinua in the t'lmracter of iLo 
pulse in disease, due to tlie iictiiin of tlie mueciilar coat, we 
ebfll) consldei- some of thcestema] modifying influences wMch 
come within the range of phj'siology. The smallest vt^seU 
and those of medium eize possess to an eminent degree what 
Id called tonicity, or the property of maintaining a certain 
contiaued amount of contraction. This contraction is antag- 
onistic to tlie distending force of the blood, aa is shown by 
opening a portion of an arterj' included between two ligatiiMB, 
in a living- animal, when the contents will be forcibly die- 
charf^ed and the caliber of that portion of the ve&sel very 
miicli diminished. Too great distention of the vessels by 
the pressure of blood seems to be prevented by thia constant 
action of the muscular eoat ; and thus the condltionfl fire 
maintained which give the pulee the character we have just 
described. 

By excessive and iContinued heat, the niu&cular tissue of the 
arteries may be dilated bo as to offer less reeiatance to the 
distending force of the hearts Under these circiiiu stances, 
the piilfio, 119 felt by the finger, will be found to be larger and 
Bofter than normal. Cokl, either general or local, has a pre- 
cisely opposite effect ; the arteries become contracted, and 
the pulse asaumes a harder and more wiiy character. UauaUy, 
prolonged contraction of the arteries is followed by relaxation, 
as is Been in the full pulse and glow of the surlaoe which 
accompany reaction after esposiuHj to cokh 

It has been found, also, that there la a considerable difie^ 

the accuracy oTreiiultE la be obtnincil wlien it la uged trith (kill aad rare; bul the 
very pprfecdon and Eiiwty of tlw liistruiiient jirt'i'c.'nt abnoAt insumiouaulile 
difflcultica in tliu v/ay of its line by (he ^eimnkl practiiioticr. ItNuliia, rcganiing 
tbc amplilude of pulsalions i>!«piKiAl1y, «ih9ui(3 luj rwei>'?<l vitb gri^t <;autiQ|B, from 
dm eiti^nio 4iS(^uliv of n^juetiug tlic Icrer so as to prs tbe muinmai of iba 
impulse It does uol appear, faowcvcr, how tticsc drawbitckn Lo Uic gcnenl use 
of ihc inslrumcQt con be obviated; fur itd cdnatruciion \e*.it» nothing to be 
■leairetl, and tho ddicary of its ndjusuncni, tiU« tbat of n. floe haJance, li indl»- 
pens-ihlc. lu tb£ hMtnlti Af Miuruj, ltd rcsiilUi we coDcrlve, ak lo be fulij m> 
wpted 




AMTEEIAL PBESBUBB, 2b 1 

eiiee in tbe calllier of tlie arteries at different pericnis of tha 
day. The diameter of tlie radial has been found very muc5i 
greater in the ereniiig than in tbe morning,' prudutiinp, 
naturally, a variation in the character of tbe puUe. We 
learn irom these phys.ioIogical variaHons, Low in dij^ease, 
when they become more eonsLtlerable, they may give 
important information with regard to the condition of the 
system. 

Preafnire of Blocd m the Arieriet. 

The reaction of the elastic walls of the arteries during the 
iatervale of tlae lieart's action gives rise to a ceHain atuouut 
of constant pressure, by which the blood ia eontinualty forced 
toward the ciipillariea. The discharge of blood into the ca- 
pillai'iea has a constant tendency to diminiah this pressure; 
but the contractions of tbe left ventricle, by forcing repeflted 
charges of blood into tbe arteries, have a compensatltig ac- 
tion. By the equiliLtrlum between these two agencies, a 
Certain degree of ten&ion lA inaintaitied in tlie arteri'^, which 
ia called the arierial presavre. 

The first experimenta with regard to the extent of the 
arterial pressure were matle by Ilales, an Engli&h physiolo- 
gist, more than a huiidreii ycare ago,' This observer, adapt- 
ing a long glass tube to the artery of a living animal, ascer- 
tained the height of the column of blood which could l>e 
fiii&tained by the arterial pi-essnre. In some experiments on 
tbe carotid of the lior*e, the blood mounted to the height of 
from eight to ten feet. Hales was not fhlly acquainted with 
tlie influences capable of modifying the aiterial pressure, and 
his cfltimates of the uonnat tension in these vefieelB were not 
entirely correct. It is now ascertained that the pressure in 
the arteries will sustain a column of about bis feet of water, 
or aix inches of mercury, and is subject to considerable vari' 



' THiixt-RaviRva, op. eit., tome iv,, p. 222. 

* Hales, Satieal ^aj/ty Locdon, 1733, Tcl. U,, SitmMtaticka, 



2C2 



ClKCDLiHOS-. 



r\r. B. 



ations, depeudiii^ npon the condition of tlio henrt nnd vos- 
Bels, the quantity of l>luud, respiration, muscular excrci&e, etc. 
AH experiments on the arterial preBsure are made on the 
principle of tbe experiment of Hales, which, with reference 
eimply to the eonfitant pressure in the ftrteriea, is as. nsetiil as 
those of later date, and ninth more &triking. The only va- 
couvenience is in the manipiilatlon of the long tube, but this 
may he avoided by setting it in a fitrip of wood, when it can 
be easily handled. If a large artery, aa the carotid, be ex- 
posed in a living animal^ and 
a metallic point, connected with 
avertifftl tube of email caliber 
and from seven to eight feet 
long by a bit of elastic tubing, 
bo secured in the vessel, tbe 
blood will rise to the height of 
about BIX feet, and remain at 
this point almost stationary, 
indicating by a Bliglit pulsatile 
movement the action of the 
heart. On carefully watching 
ihe level in the tube, in addi- 
tion to the rapid oscillation co- 
incident with the pnlse, another 
oficillation will be observed, 
which is less fre(|uent, and 
which oorrespoDdB with the 
movements of respiration. The 
pressure, as indicated by an 
elevation of the flnid, is slight- 
ly increased dimng expira- 
tion, and diminished during 
inspiration.' 

' fn all (hose oxi>crin>e]ita on the arterial or carcIUc prcivare, It Ib PCC M i T y 
to fill purl of itc luhe, or whaterer ■pgiarn.tiLS irc maj use, Wllb a Botution ofctr^ 
boEv)!; of AQtlfi, IS DTtJer to prevent cosgul^tion of tlie b-lood Kt It iNtUM- tiat of 
the Teasels. 



HBlludjiiiaiaDi«U!r nf Pol •full If, lU'OillBeJ 

bT LnilH'it, Pfirtigltr. turl V»l.f!iiilfl. Tlio 

Initmmi-ut 1b i7oi>nci'teil Kith tb« vpakI 
V y. Id BUftb t innnncr (hat llie tlrcnla- 
Unn i* uiil lnU'mipt*il. Tlip cU'Tiiilin of 
Ihe nitrnirr In ibC' bmich D C tadlTAUl 
Ibo Biniiiuiit (if prcoiLw. ( BECLj-Bti, J^y- 
tielitgif, llrli, 1B3II, p. Sm.)- 




rERTAL PHES8USE. 



203 



The experiment witli tiie long tube gives ua tlie beet idea 
of the arterial pressure, whicli will lie t'uutiil to vary trom live 
■nd a lialf to sis feet of l)Ioo<l, ^- "<■ 

or H few inches more of water. 
Tlie oftcillatLonB produced by 
tlie contracttone of the heart are 
Dot very marked, ou ac^countof 
the immense friction m &o long 
ft tobe ; but tLi& is favorable to 
the Btiidj of the constant preas- 
ure in the Jirteriea. It has been 
fonod that the estimates above 
given do not vary very Binch 
in animals of ditFcrent sizes. 
Bernard found the pressure in 
the carotid of & horse little 
naore than in the dog or rab- 
bit. In the larger animals it 
18 the force of the heart which 
ia increased, and not tu any 
considerable extent the con- 
•rtant prebsnre in the ve^ielB,' ' 

The experiraenta of Hales _^_ 
"were made with a view of eal- •> -^ 



culating the force of the heart,, ^^^'.Tfl.;:^ b^'ne^r?^^ 

and were not directed particu- 

lai'ly to the conditions and Vnr 

riationsof the arterial pressure. 

It is only emce tlte experimenta 

performed by Foisenine with 

the hcemadynamo meter, in 

ISeS, tliat we have any reliable ^^' """*^ *" ''^■' 

data on this latter point.' PoiseuiUe'a instrument for nieasni^ 

ing the force of the blood is a simple graduated U tube, half 

'■ BXRXARli, lA'pti^'t de rOrffanUme^ Paris, ISBfl, tome L, p. 172. 
• PoisiCitu, Hfthrrcha lur ft Forw rfw C«itr Aorfigvf, Parie, 1828, 



bottle 

it pirflmttid Rt each <ti1", nnii fiti.nl wtll] RU 

"iftu tntw, with u ai>«[]lDii< T. >iy whlcti <ba 

morcnn enlcnL Onn aoil of Uio Ithd tube 
Uol09«O.SQr1 the niljifr I* t>«nt iijHFFirdii and 
roDDr^'loiI with lliL' vr»d>iAt.ed {tIum taSe T'. 
Vibld) bf|.*Acii]!]irT of from ^( Ko-^ of an ^n?^ 
TImi bolllt' l» IlUt.1 Willi nji'rrnrj-uiitll It 
rliuton'tn thi< 1»l>n wbk'b la iDiiitLi.>d. Q, 
The Cork la pcrTonitcil by tbp lube (, n-hlcJi 
1i uoDrp'ptod by a inliberiabowUhtlio gMiInt 

C. wWcb It 1lltrrji1Ut*rl 1r.l6 Ih* TPBSvL 
(Reex^rD, rji/'itiin lit r Organ irtnt^Tnit, 



264 



ORCDfJlTION. 



rif.^ 



fillet) with mercury, with one arm bent; at a right angle, so 
that it can easily be connected with the artery. The prciss- 
ure of the hlood ia indicated hy a depression in the level of 
the mercury on one side, and a corresponding elevation on 
the other. 

This io&truiiient is generally considered m poeeeesing 

great adrantagea 
over the Ion? glass 
tul>e ; hut for esti- 
mating fiiiu|i!y the 
arterial pressure, it 
ismufh lessnsefnl, 
ns it is moreeenai 
tive to the impulse 
of the heart. For 
the study of the 
cardiac pressure, it 
has the disadvan- 
tage, in the iii'st 
place, of conaider- 
ahle friction ; and 
again, the weight 
of the column of 
mercury prodttces 
an exten t of osciila- 
tiuii by ite- mere im- 
petUB, grenterthan 
that which would 
actuatlj represfsnt 
the tbrce of the 
heart.' 

"" ~ " ' An important 

ftuit, Htm. p. !«). improvement m 

' Ladwig d6t^s«j a means of rcf^aring the oscilktLon in tlie hiBni«dj- 
nftiaonMiUr of ro)«cui.l1e. He used a U tulne of ccinHitlvrmble hxc, &nd plicixl ■ 
3oat nil tlie STirfj,i.'o of tilt nHTCurj, to wlijcli b jtmdl was ■llavhi'd Th-? point 



^KTtBIAl, CKEsStmK. 



SHS 



thelia-madynamometer waa made by Mng;enclie. This ap- 
parntnw, the cardi&mftei\ in wliicli Bernard liaa made soma 
important mod iti cations, ia the one now generally used. It 
consists of a small but thick glass bottle, with a fine graduated 
glaa^ tiibo alxmt twelve inehea in length, cOTtimunicatiog 
with it, either through the stopper, or by an Qrifice in the side. 
The stopper is pierced bj a bent tube which is to he connected 
witli the blood-veseel. Tha boltits is filled with mercury bo 
tiial it will rise in the tube to n point which is marked zero. 
It is evident tliat the amount of pressure on the mercury in 
the bottle will be inch'euted hy an elevation in the graduated 
tube; niul, moreover, from the tineuesa of the column in the 
tube, we avoid some of the inconveniences which are dne to 
the weifjht of mercury in the haimadytiainometer, and al&o 
Lave lebs frictiou. 

This in&trnment is appropriately called the cardionieter, 
as it iudieates most accuratety. by the extreme elevation of 
the mercury, the force of the heart; but it ia not ae perfect 
in its indications of the mean arterial presBure, as in the ab- 
nipt descent of the mercury during the dinstoleof the heart, 
the impetus causes the level to fall conaiderably below the 
rertl standard of the constant pressure. Marey has euceeeded 
in correcting this diftit:Tilty in what be calls the " eompensat^ 
itig" inatrumeut ; which is constructed on the following prin- 
ciple: Instead of a simple glass tube which conimuuicates 
with the mercury in the bottle, aein Magendie'a cardiuineter, 
he hae two tubes : one of which is like the one alrcntly describ- 
ed, aud represents oscillations produced by the heart ; the 
other is larger, and has at the lower part a constriction of 
the caliber Avhich is there reduced to capillary fineness. This 
tube is designed to gire the mean arterial pressure. The 



of (he pencil, brought in crtnlnct witb a rerolTlng cvliodtr covered with paper, 
proilucvd Ji irui'i' of the o s cilia liona. By analysis «r this irace be arrived ti the 
in^aD jirvesiire in the artericn. Tlii:^ instruiiictit, imiIIciI the ti/inixii'ap/iitjHj \\aa 
neveT been uun'h aavd in i(iri»giiiiHlmii, anil i-« puiiTely auper»eilt;iJ lij tlw cnr4i»- 
meWr. (Lpdwio, f^Aytiafajle, Leiprig iind HeidelbuTg, Iflfll, Bd, !!,, S. 123.) 



266 



oracnLATios. 



cajnstriction in the tube offei^ such an obstacle to tlie rxie of 
the niercurj that the iuteraiittent aetioa of the heart h n(>t 
le!t, theniercury rising slowly to a certain level, which is con- 
Btant, Rcd varies only with the constant pressitre in t!ie veesela. 

We have only an npj^rosimatire idea of the average pi-ess*- 
iire in the arterial syatem in the human subject, d&hiced from 
experiments on animals. It has already been stated to be 
equal to about ais feet of water, or six inches of mercory. 

The most interesting questioDS coaoected with thie eab- 
ject are; the comparative pre&suro in different parts of tlie 
arterial Bysteni, the inflQeneea wliic!i modify the arterial prras- 
ure, and its influence on the pulse. The&e points have all 
been pretty fully inveati^gated by exi^eriments on animals, and 
on gystems of elastic tabes arranged to represent the vcbscIb, 

Pressure in Different Part^e of the Ai-teriaZ Sr/etem. — 
The experiments of IIale&, Poiacuille, Bernard, and others, 
Beem to show that the constant arteriu! pressure does not vary 
in arteries of different aizes. These phyaiologista have ex- 
perimented particularly on the carotid and cruraJ, and have 
found the pressure in these two vessels about the same. 
From their experiments, they conclude that tbe force is 
equal in all parts of the arterial system. The experitnent* of 
Yolkinann, however, have shoMTi that this conclusion ha^heen 
too haetj. With the registering: apparatus of Ludwig, he has 
taken the pres&ure in the carotid and mt'tatursa] arteries, and 
has always found a considerable difference in favor of the 
former.' In an experiment on a dog, he found the pressure 



' For compsriDg^ tbe pressure Id diO^innt reaacli uid in different aniniiU, 

Bcmaril baa i!(-vis4?d aii ioj-tnjment whidi hec&lb the difermHalAamaJj/inuHO- 
tnetett It conaista of a graduated f tube bd nmogcd tbat botii Krtus tr\ay be 
■imu]uuiM>UBljcoiiDcctc(t iriUi ^epamtc Testis. JT the prcsBiirebDeqiu) In lh« 
tno tfe^eda Hith wliJeh tt JB coDDCctcd. tbe lerol of the mermr; will oot be tffecU 
(hI ; but aa iDE^ualit^T of pressure will be marked by •. deprewiioti of tbe mereurj 
In i1ie aj-Qi coirespondbig tu the vessel !d wbicb the prossMn!' Is the more poirn^ 
fuL With tluB liu.trum«nt, Bernard uasumei to hayt; dvotpustrpLed thht llj« «ifr 
Ii4tn( pret^ure is equaJ in all ports tff tiie arteiial syabem, ths force of tlie tKcrd 



AXTEBU-L PRESS CBE. 



267 



equa} to 173 mUlimetros in the carotid, aud 165 mm. in the 
nietataraaL In an experiment on a eiilf, tlie pressure was 116 
mm. in the carotid, and 89 mm, in the metatarsftl ; and in a 
rabbit, 91 mm. in the curutid, and 86 mm. ia the caiiral.' 

These experiuieiit?, which Beem to have been performed 
with great care, show that the pressure is not abaoliitelj the 
same in all part^ of the arterial nystera ; that it iB greate&t in 
the arteries nearest the heart, and gradually dimiuiBhes aa 
we near the capillaries. The difference is very slight, ahuo&t 
inappreciable, until we come to veasela of very small size; 
hut here the pressure is directly influenced by the discharge 
uf Uood into the capillaries. 

The cause of this dimititition of preBsure in the araalleet 
vessels is the prosiiuity of the great outlet of the arteriee., the 
capillary system ; for, as we eliall see farther on, the flow into 
the capillaries has a conatant tendency to diniiniBh tlie prosa- 
ure ill the arteries. It ia obvioufi that this infliieuco can only 
be felt in a very marked degree in tlie vessels of emalleat Biz&' 

Iiiji-u^nce of Itespiratlon. — It ia easy to see, in &tndying 
the arterial preasnre with any of the instrimiontB we have 
described, that there ia a marked increase with expiration, 
and a diminution with inspiration, The fact that expiration 
will increase the force of the jet of blood froifi a divided 
artery has long been obBBTved, and aBcorde perfectly wUb the 
above statement. 



only, lUminEahmg b the araaller ves9cl«. The inatmnoient bj M tfleMB pDas^SM 
llie dt'lii-atT of tlic appRratus us<k1 bv Viilkuiann, Id glTiog iha melLn prraSure. 
^Liqtiidet de V Qr^anitiite, tipnii- i., p, 200 et if^.) 

' Milnk-Edwauds, op. alt., lom^ iv., p. 284. 

* rhin v3tw Ls ruil^ tsiusiAiced liy pliysival Iuvtb. IT fl>ii<] be <IiBt;1]iirgecl fWtiii a 
teeervolr by a Ioqjj boriztiiiid tube of umforui wJibcr, tbu pressure, ns indicated 
by reni(!iLl tubes at d)ffereut points, will be found to Jiiiiinbb regularly JVom tbe 
h«iglil «f the Quid ia IIjo reserroir to Llie orifice of dbi'bii^e. An inBlrunienC of 
llua kjuif, Kbkh Ia vMcA n /nrxuiiitlrr, ebotia tlic ttfiparent pliJ'SLcni bCc&SjjLjT 
of n progressive diminutloD in pri^uure lu the art«ri&l Bj^stcm, u we pasd tcom iho 
heart W the capillnries. 



2C8 



dBCULATlOBT, 



In tranquil respiration, the inJiuence upon the Bow of 
blood is due siitiplj to the mcchauicul action of Hie thorax. 
With every inspiration the air-<jeUa arc enlnrged, as ivell ns 
the hlood-vt^els of the lun^ifs; the air ruslies in through the 
trnchea, and the movecueut of the blood m tlie veins near tJie 
clieat i& accelerated. At the same time the lilooiJ in tlie arteries 
i& Bomi-what retarded in its flow from tlio Ihorax, or at least 
doeB not feel the expulsive influence wbicli tbllows with tho ict 
of expiration. The mean of tho arterial presaui-e at tliat time 
ia at its minimum. With the espiratorj act, the air is ex- 
jjelled by compreBSion of tho luu^, the flow of hlood into the 
thorax Ijy tlie veins is retardL-d to a certain extent, while the 
flow of blood into the arteries ifl favored, Tliia is strikingly 
exhibited in the augmented force, with expiration, in the jet 
irom a divided artery. Under these circumetanees the arte- 
rial pressure is at its maximum. 

In perfectly tranquil respiration, the changes dne to in- 
spiration and expiration are very Blight, marked by a differ- 
ence of not morij tiian half an inch to an inch in the car- 
diometer. When the respirato]7 movements are exaggerated, 
tlie oscillations are very much more marked. 

Interruption of reepiration h followed by a very great in- 
crease in the artei'ial pre^ure. This is due, not to caneee 
within the chest, but to obstraction to the circulation in the 
capillaries. We ara already aware of the influence which 
the flow of blood into the capillaries ie eonfitantly exerting 
upon the arterial pressure. This tendency to diminish the 
(quantity of blood in the arteries, and consequently the 
pressure, is constantly counteracted by the blood sent into 
the arteries by thecontractionu of the hoart. In interruption 
of the respiratory function, the non-iierated blood pae&es into 
the arteries, but refuses to pusa through the capillariea; and 
as a consequeuee, the arteriee are abnormally distended^ and 
tho arterial prfssure is, enormously increafied. If respimtioti 
he pernmnently arrested, the arterial pressure becomes, after 
a time, diminished below the normal standard, and ultimate- 



ABTBEIAL FBEB8UBB. 



2r>9 



ly nbolislied, on account of tho stoppage of the action of the 
heart. If rtspiration be resumed before the heart La? become 
arrestyd, tbo presatire soon returna to its normal stRnOard. 

Muscular effort coneiderably increases the arterial presa^ 
ure. Tiiie is Jho to two eaiises. In the first place, the cheat 
IB genemlly compreseed, favoring the flow of blood into the 
great vesseK In the second place, muscular exertion pro- 
duces a certaui amount of ubntructiou to the discharge of 
blood fruui the artcricd iiitu the capillaries. Nnmorous ex- 
periments upon animals have shown a great increase in presa- 
ure in the sti'nggloa wbltb occur during severe opcrfttionB. 
Bermird lias eho^vii that galvanization of the sympathetic in 
the ueck and tmlatioa of eome of the cerebro-spiJiaJ nervea 
increase the arterial pressure, jirubably from their eflectB oa 
the muBcular coats of &oinc of the arteriea, causing them to 
contract, and thereby dhuinishing tlie total capacity of the 
arterial ByBtem.' 

^'ecf4 of Iffein^rrAa^s. — Diniinntion Jii tbe quantity of 
blood hft3 a remarkable effect upon the arterial pleasure. If, 
in oonaecting the int>trumeat with the arteries, we allow even 
one or two jets of blood to escape, the pressure will be found 
diminished perhaps one-half, or even more. It i« hardly neccB- 
eary to diwjuss the inechanisui of the efl'ect of the loss of blood 
on the tension of the i'CBscls, bat it ia wonderful how soon the 
pressure In the arteries regains its normal standai'^d iii\cr it has 
been lowered by hwmori-hage. As, it depc-nda upon the quan- 
tity of blood, as soon as the vessels absorb the eeroeities iti suf- 
ficient quantity to repair t!ie loss, tlio pressure is increased. 
This takes place in a very short time, if the loss of blood be 
not too great. 

Experiments on the artcrinl pressure with the cai-diometcr 
huve veri fled the fact stated hi treating of the furm of the pulae, 
namely, that the pressure in the veasels bears an inverse ratio 
to the distention produced by the contractions of the heart. 

< BcKifutn, LufuiJr* It ^ Orifaiiimie, Parii, 1S09, tome L, p. 341, df Kg. 
IS 



UiU CmCULATTOS. 

In the cardioineter, tlie lueau height of tlie mercury inJieatee 
the couatant, or arterial, pressure, mid llie oscillations, tiio 
distention iirodmietl hy the heart. It is found that when tlie 
presfiiirc ia ^eat, the extent of oscillatiun ts small, and vice 
ver^tii. It will be remeinbei-ecl that tlie ^p.tleal^ehes of Itare^ 
denioiistrated that an iocreafle of the nrterhil pressure diniui- 
islies the amislitucle of the pnlaatfons, as indicjil&l hy the 
sjihygniograph, and that the amplitude ia very great when 
the pressure is slight. 

It 19 aUo true, as a general rule, that the force of the heart, 
as indiciited hy the cardioiueter, bearg an inverse ratio to the 
trequeuuy of its pnl&ationa. 

'S'ummar//. — Tlie arterial pressure, due to the distention 
of the arteries, and the reaeticjn of their elastic walls contin- 
ually forcing the hlood toward the capillaries, ifi equal to 
about six feet of water or six inches of mercury. It is in- 
creased by any thmg which favore the floiv of hlood into the 
great ves^elfi, like the cxplratorj act, or by any thing which 
ob$tructs the flow from the artercolcs into the capjllarifs, 
like muscular effort, contnictiou of the rauacular coat of the 
smallest arteries, or non-aeration of the hhxKl. It ia^niLn- 
iahed by any coneidcrablc diuiiniitiun iu the quantity of th« 
I'ircidatiiig fluid, or by any thing which facilitatee the pastiage 
of blood through the capillarieii. 



Ea^id'fy of the Current of Blood in the Arienm. 

Though this is not a question of great physiological im- 
portance, it is a point of some interest. It lias long engaged 
the attention of phvBiologi&ts, and has hitely Ix-en made the 
Erubject of some curious and iugeoious experinieute. Paesiug 
ovLT the Bpeeulutions aud calculatian& from impertect ]>hy&E- 
cal data of the older phyfiiolu^ittfi, which led to no detinJCc 
i-esulta, we tind the lir&t experiments on this subject made hy 
Yolkmann, with an uid.trunient eaUedthehiinnadronionietcr. 
This appai'atus consists of a U tube, graduated, and so ar- 



lUFmnr ob" ruB aetebial circui.atioh. 



271 



ranged that when the inBtruraoDt is connected with the orterj 
of a living auiinaE, the current may be indtantaneouBly tli- 
reetei] through the gradnated tube, and by a stop-watch, tho 
lengtU ol' time oecapied lu passing from one extremity to 
the Qtber accurately mwisured. Observiitious with this iii- 
etrumciit, on the rapidity of tlie circulation iu the carutid, cif 
the do{5 and horse, show that the hlood moves at the rate of 
from ll> to 13 inches per secuiid. Tho rapidity is diminish- 
ed in the smaller vessels, being hut *2'2 inches per tecond in 
the metatarsal artery of a horse, and 10 inehea in the carotid.' 

The results thus uhtained cannot Ix) received as absolutely 
exact. The blood in diverted from its natural course, and 
must exi>erienee a certain diminution in velocit}- from the 
curves in the tnbea. It la also evident that the normal cur- 
rent ib not miiforui ; that it ia much more rapid iui mediately 
atler the gy&tole of the heaii, than daring the diastole j and, 
as has been deiuoiistruted by Miu'ey, the blood in the arteries 
undergoes a certain oscillation. The experiments of Volk- 
mann give an approximative idea of the mean rapidity, it is 
trut't hut they eu'l* far from exhibiting the natural ctirreut, with 
the variations corresponding to tlie movements of the heart, 

A few yeara later (185S), an inatniment was devised by 
Vierordt, which seemed to embody the right principle, hut 
it was not soiScientty sensitive to accomplish all that was dc- 



' The eipGrimenla of Volkm&nn and Hiittenbcim, publUhetl in Iftlfl, are «f 
feiTod to, a.Qil the itajtriiisciit tleacribiid aiiil ilL'littM.ti3d, in moat wgrks do plirsiot- 
u^v. Wh«!ii till! inelnimcnt is flp't qg^ncct^ ^Ub tbo nrtccj, tbe blood purses 
tlirougb a WBJg^H bi\>K; ami \a riot duviali^ from 'Ua trourat;, Tb^} cunvnt is 
div-ertL'J iutff tlm gra>luittv<l V tuba b; cwo siop-cuvka wliluli lire iurungi'd so that 
tlicj niuj be lumvU eiuialtaDwusly. Ucibrc it ia &pp)iL'il, tbo nppnratuy ia fiUtni 
wiih warm whIlt, so ah to prevent the entrimtc of air into the tusscU, 

The followiii[j are tho re^ulta Dblalncd by Volkmaua in esijerimtaia oa dfiga 
and lioraua: 

lb Ihi) (ioji earolid .... 10-7 indies per iewnd. 

tia, da. . , . . 13 '• ■* •■ 

In llie liorse, parotLO . . . . 10 " " '* 
do, meMnTsal nrtsry . . 3-2. " " " 

— Losorr, ThtUi de piythlfiffie, Ptna, 1869^ tome il., p. SO*. 



273 



cificrr-ATiox. 



sired. It con^iated of a iittic square bos made of gtnss, witli 
ail opening at (■aeli end, by which it was to be coimeuted » illi 
the artery. Tbifi tB filled with water, and contnius a pendu- 
lum, whicb ia stnicb by the current of blood. The deviations 
of the pendulum are miirkcd on a stale. After this has 
been a^ipHed to an artery, and the extent of movement of 
llie 2)eiidiilum noted, it is removed from the vessel and con- 
nected with au elastic tube, ia which a cnrreat of water is 
made to puss witli a degree of rapidity which will produce 
the same dei'iation as occurred when the instrument was con- 
nected with the blood-vfB&el. Tlio rapidity of the current in 
thia tube niny be ensily calculated by receiving' the fluid in a 
graduated vessel, and noting the time occupied in di&ehiu^ 
ing a given quantity. By tlds means we ascertain the 
rnpidity of the current of blood. By nneans of a needle 
attached to the pendulum, the oscillations could be regis- 
tered on a revolving cylinder of paper, and the mean veloeity 
taken. 

"With thiB-instrumentiVierordt estimated the mean velo- 
city of Mood in the carotid at 10-2 inches per second. Chau- 
¥eau, who invented an iu&tnimeut which we M'ill describe 
pi-eBently, found the infitruiuent of Vierordt not BufHeiontly 
sensitive, and requiring so ranch earo and [-recaution in its 
uae aa to essentially dtnnoish the value of it* results. 

The b^t instrument fur measuiing the rapidity of the 
etrculntion in the arteries was deviscil by ChauvesH, of the 
Veterinary School at Lyons.' Tlti* will give, by cidciila- 
tion, the actual rapidity of the circulation ; and, what ismoi-e 
interesting, it marks accurately the rapid variationa iu velo* 
dty, with reference to the heart's action. 

The instrument to he ajiplied to the carotid of tbo 
hyree coueists of a linn brass tube, about IJ inch in length, 
and of the diameter of the artery (about | of an inch), which i^ 



' MM. A. Cn*rTKAir, G. BBatOLca et L, LAnoVE^SE, I'lma de la CtrfuInlioH 

ii'im Ic* Arl^i'ta du C/irial. — /oufnal d« lii Pf^jf^iJujie, raris, 1880, louw iii. 

p. r«5. 




window, near the 
Tiiiddle, about two 
lines long aud yiie 
Jine wide. A 
I'iece of tliin vul- 
ciiiiiied rublier is 
wiiijnd around the 
tube, and tintily 
tiedj so as to rov- 
er this opooinff. 
Through a tratis- 
verse slit in the 
rubber is intro- 
duced aver}' light 

inctaliiu lieedlo Chnow'iiu's iDHmtiii-fit f^r mtiL-nrljij.- tin- rtfildllj' af th* Biiw »f 

5 tbod Iji till' nrwrUtj, Tim luatnmniot vlowi'il In fii"*— n, lb* 

un iiifli anil II linlf ^""^ ''■ ^"i ^-^ In Uiv rnArl; Ij, Uip (LI*I wbkb watbi tlb^ex- 

an luiJi mm a iiitii ^^, |,, nioinnnnt nf He bowIIb J; «, ■ Inlmil luU- forth* 

iu IcUi'th and fllit- *'lc*'^'u')eiit4(ae«dIoaiei«f, It d««lPMl. — CiUDTXAcr, op. sit, 

tened at its lower purt. This is marie to project about half 
waj iJito the calihei* of tho tube. A flat Bemiuircular piece 
of metal, diWded into an arbilrarj acale, is attached to the 
tube, to indicate the devisitiaiift of the poinl of the uoedle. 

Tlie apparatus i* Iiiti-o>Juced carefullj iuto tho carotid of 
A hoi'se, by makiug a slit ia tL,o resselj intri^ducuig fret one 
end of the tube, directed toward the heart, then alluwing a 
little blood to enter the iu&trumeut, so as to expel the air, 
and, when full, introducing the other end, securing the whole 
by ligatiircB above and below. 

When the circulation ia airested, the needle should be 
vertical, or mark zero on the acale. When the flow is ofstab- 
lished, a deviation of the needle oocurB, which varies in cxteut 
with tlie rapidity of the current. 

Having removed all pressure Irom the veaeel, &o as to al- 
low the cun'eut to resume it& normal character, the deviations 



274 ciBcni.ATioK. 

of the needle are carefully noted, aa they occur with the sys- 
tole of the heart, with the diastole, etc. After withdrawing 
the instrument, it is applied to a tube of the size of the ar- 
tery, and we measure the rapidity of the current required to 
carry the needle to the points noted, which may be done by 
the same calculation used in graduating the apparatus of 
Vierordt.' 

This instrument is on the same principle as the one con- 
structed by Vierordt, but in sensitiveness and accuracy is 
much superior. In the hands of Chauveau, the results, par- 
ticularly those with regard to variations in the rapidity of 
the current, are very interesting. 

Rapidity of the Current in the Carotid. — It has been 
found that three currents, with different degrees of rapidity, 
may be distinguished in the carotid : 

1. At each ventricular systole, we have, as the average 
of the experiments of Chauveau, the blood moving in the 
carotids at the rate of twerUy -^ inches per aeoond. After 
this the rapidity quickly diminishes, the needle returning 
quite or nearly to zero, which would indicate complete 
arrest. 

2. Immediately succeeding the ventricular systole, we have 
a second impulse given to the blood, which is synchronous 
with the closure of the semilunar valves, the blood moving 
at the rate of eighi ^ inches per second. This Chauveau 
calls the dicrotic impidse. 

3. After the dicrotic impulse, the rapidity of the current 
gradually diminishes, until, just before the systole of the 
heart, when the needle is nearly at zero. The average rate, 
after the dicrotic impulse hjt've -^ inches per second. 

These experiments give us, for the first time, correct no- 
tions of the rapidity and variations of the flow of blood in 
the larger vessels ; and it is seen that they correspond in a 

' In graduating the apparatus, Chauveau uses varm water. It would be 
more Kccurate to use defibrinated blood, or a Quid of equal deneitjL 



RApmrrr of xnE akteeial cmcuLATioN. 275 

remarkable degree with the experiments of Marey on the 
form of the pulse. Marey showed that there is a markefl os- 
dllation of the blood in the vessels, due to a reaction of their 
elastic walls, following the first violent distentiou by the 
lieart ; that at the time of closure of the semilunar valves, tlie 
arteries experience a second, or dicrotic, distention, much less 
than the first ; and following this, there is a gradual decline 
in the distention until the minimum is reached. Chanveau 
shows by experiments with his instniment, that correspond- 
ing to the first dilatation of the vessels, the blood moves with 
immense rapidity; following this, the current suddenly bo 
comes nearly arreted; this is followed by a second accclcra- 
tios in the carrent, less than the first; and following this we 
have a gradoal decline in the rapidity to the time of the ncxl 
pulsation. 

-Rapidity in Different Parts of the Arterial Syafcm.— 

'**oin the fact that the arterial system increases. in capacity 

■s Tre recede from the heart, we should exjiect to find a coi-- 

'^^ponding diminution iu the rapidity of the flow of blood. 

/■■"©** are, however, many circumstances, aside from simple 

^^'"ease in the capacity of the vessels, which uudoubteilly 

'^^^^tiify the blood euri-ent, and render inexact auy calculations 

f5* X*«rely physical principles ; such as the tension of the 

^**o<3j the conditions of contraction or relaxation of tlie 

"**^lle8t arteries, etc. It is thereibre necessai-y to have re- 

***Tee to actual experiment to arrive at any definite results 

?^ 'tliis point. The experiments of Volkmann showed a great 

"''•Bixnce in the rapidity of the current in the carotid and 

. ^"^^^tarsal arteries, the average being 10 inches jier second 

.. ^le carotid, to 2"2 inches in the metatarsal. The same 

^*srence, though not quite as maiked, was found by Chau- 

^'a. between the carotid and the facial. 

jChe last-named observer also noted an important uiodifi- 
"^tiOii in tiie character of the curi-ent iu the smaller vessels. 
^^ "^-e recede from the central organ, the systolic ini;nilse 



276 



OlECrLATION. 



becomes rapidly diminished, being rerlnced in oneesperimcnt 
about two-tliifds; the dicrotic im[j'ti]fit' becomes very feeble or 
even abolialied ; but the ci)n5tBnl ilow is very much increased 
hi rapidity. This fhct caiwculGs with the ideas almady ad- 
vanced with regard to the gradual coDverisian, by virtne of 
the elaaticity of the vesi?els, of the impul&e of the heart into, 
first, a remittent, and, in the very smallest arteriica, a nearly 
constant current. 

The rapidity of the flow m any artery must be subject to 
coratfint mw!ificatioii& due to the condition of the arterioles 
which are supplied by it. TVhen these little vet^pfU are di- 
luted, the artery yf covu"se empties itself with greaxw facility", 
litid the ra])tdity is increased. Thus the rapidity beare a re- 
lation to the arterial prcsBiirc ; as, independently of a diini- 
nutiun in the entire quantity of the circulating flnid, varia^ 
tions in the pressiiro depend chietij* on causes whieh facili- 
tate or retard the flow of blood into the capillaries. A good 
example of enlargement of the capillaries of a particular part, 
is In mastication, when the ealivarj glands are brought into 
activity, aud the quantity of blood which they receive is 
greatly increased. Chauveiiu found an iuiraenee increase in 
the rapidity of the flow in the carotid of a horso during mas- 
tication. The cnhirgement of the vessels of the glands during 
their function has Ijcen conclusively proven by the cxi»eri- 
iiienta of Bernard. 

It must be reujcnibered that in all parts of the arterial 
eystem the rapidity of the eun-ent of Mood is constantly liable 
to increase from dilatatioji of tlie &tu:ill vessels, and dimlntitlon 
from their contraution. 

Arterial Murmurs. 



Jxi the 'Inrtrest vessels, we cian frequently hear with lie 
BtethoEcope the sounda conducted frotu tljo heart, In addi- 
tion, wu can Lear, in all except the stnallest vessels, a pecq- 
ll'ir blowing Boundj called the bruU de aou^e, whjcli it 



ABTEBUX HUBUCKS. 277 

produced by the pressure of the end of the instramcnt on the 
artery. The following is the ineehaniBm of the production 
of this sound : The pressure of the instrument produces a 
constriction in the vessel, and more or loss obstruction to the 
corrent of blood. As the blood flows from this constricted por- 
tion into that just beyond, where of course the vessel is rela- 
tively larger and the current is somewhat retarded, the rela- 
tively small and forcible stream produces an unusual and 
irregular current, which is accompanied by a certain sound. 
It has been proven by the experimentti of Chauveau and 
Marey with elastic tubes, that this sound is alwa^'s produced 
when any part of the apparatus is dilated so that the fluid 
passes from the tube into a sort of sac. In this way aneuris- 
mal murmurs are accounted for. The sounds which are 
heard in the arteries, and are not dependent upon compres- 
sion with the stethoscope, depend upon conditions, the con- 
Bideration of which belongs to pathology. 



CE^IPTEE Vn. 

OtRCULATlON OF THE BLOOD IN TITE OAPHXAaiES. 

DiatincEinn bet»m>n eiipilliirsi.'a aaA \h,e BrDalli>«l ndCTiE!? nml teidb — PlirBiolog;ii.»l 
■.Diitamy of th^ oFip!lllai'i>.>«i — Puculinritliis of dLitrit'ii'tiQii— Cajuiuity uf tti« 
oupLlljiry ^ysiem — Coiir*o of Wood in ihc raiiiHnrics — FlieDoiwoi of the 
cnpilUrv <:irculation — Etnpiiilty of iLq uagjillary i.-JrcuLnticia — Kvktiotu of tb« 
rapLllary circuliition to reflpirilian— dmees of tho mjuUary circiiUtioD — la- 
fltieacc of lcnkp>artiturc on Uie capitlitrj circulAUon — InAucH'Ce of ilirt-cl irnU- 
Qon on tbe (apiUBif circuUtion. 



Befoee entering upon tiie study of the capiUaiy circu- 
lation, let 118 define what we mean hy the capillary veesels, 
aa diatinguislied from the emalleet arteriee and veins. From 
a atrictly physiological jiuiut of view, the capillariea ehoold 
be rcju'arded a& fommeucing; at tlie point wliere the blood is 
lirought near enough to the tissuea, to enable them to aep- 
arato tho elements nect-ssarj for their regeneration, nnd gire 
vip the products of their physiological decay. With oar 
preseut knowledge, it is impoBsiblc to a^iga any limit where 
the vessels cease to be simple carrierB of bJood; and it does 
not aeera probable that it will ever be known to what part of 
the vasuular system the proceefics of nutrition are exclusively 
srtuiineil. Tiie divisions of the blood-vesaek must he, to a 
certain extent, arbitnirily defined, and we should feel at lib- 
erty to adopt the ■views of any reliable obecr^'er with regard 
to the kind of vessels which are to be c-onsldf^red as uipilhi- 
ries. The most simple, and what seems to be the most pliy&- 



rSTSIOLOOICAX ASATffSIT OP TnK OATTLL&JtTES. 



iologicftl view, is to regftrd ns capiUariee those vceseU ■vrliicli 
have but a einglo tuniu ; fur, in these, the blood is brought 
in closest proximity to the tissues. Vessels whieh are pro- 
vided, in addition, with a muscular, op with muscular and 
fibrouH coate, fire to be rcgjtrded na cither email arteries or 
vetLOHs radicles. This view is favored by the character of 
the currents of blood, rs seon in microscopical observation 
of the circulation in ti-anspat'ent parts, Uere there ia an 
imput&e observed with each contraction of the heart, until 
wo come to vessels whieh have a singlo cuat and nre so 
narrow as to dllow the passage of hut a aingle line of blood- 
corpuscles. 

Phtjxlolotfical Anatomy of the Capillaries. — If thcnrCerics 
be followed out to their miuutcst i-aiuilicatluuB, they will be 
found progressively diminighinp in nize as they branch, and 
their coats, eepet-ially the niiisciilar, becoming thinner and 
thinner, until at last they present an internal, etruetiireless 
coat, lined by epithcliuui with oval, longitudinal nuclei, a 
middle coat, formed of hut a single layer of circular mus- 
cular fibres, and an external cont, composed of a vety thin 
IftVer of longitudinal fibres of the white inelastic tfeene. 
These vesseLe are from -^-^ to j^ of an inch in di-imcter^ 
become Buialler as they branL-h, and undoubtedly possess the 
property of contractility, which is particularly uiarked in the 
arterial system. Follo^vin^ the courBe of the vessels, when 
they arc rodneed in size to about j-J-,,- of an inch, the external 
fibrous coat is lost, and the vessel then presents only tbe ui- 
teruftl co&t and the tingle layer of niuecular fibres. The vcs- 
Bels become smaller .le they branch, fiiaiiUy lose the nniseular 
coat, and have tlien but a eingle tunic. These, the veaacU 
of the first variety, according to the claesification of Rohtn,' 

' Littb£ ct RoDCti, DidioKnain A Midttint, Paris, 1ST3. Article, dtfilMre. 

Th« diviBion of tlie cnpilkticB irlo three Tarictice — ilie flrft wiili r 
homopuncoua Cftnl, th* second with the aiidilion of n mnifculiiir i-iml, and tlic 
third irith ft mnscnlar and u fibroai conl-^vna matlf bj IIenk>, and in, pei'l»ip«, 



280 



CrRCT:U.TION. 



wbo recognizes three varieties of capillnries, wo frliall con- 
sider as tlie true capiUary vessels, 

Tlie miuutu structure of the capillar}- vessels is of con- 
eidemhle importance and interest, and Laa been very elosely 
invcwti'gated M'ithin the last few yeavs. It was formerly 
tliouglit tlint the Btnaliest vesBclB, whicK Tve deecribc as the 
true CApniarics, were coinpoBed of a single, lioniogeneotifl 
meiiiliraue, from Y^hrv ^^ tb*bt '^^ ^^ '"'^^' ^liick, witU nuclei 
embedded in its substance, but not provided with an eju- 
tlielitd lining, Kecent observatious, however, have shown 
tlmt the membrane is homoireneoiis, elaetic, perlmps eon- 
tractile, and, in same parte at least, is prr^vided with f iitjiform 
or polygonal epitlieli;im of exeeesivo tenuity. The borders 
of these eclls may be seen by fitasnin;^ tlie vcseels with ni- 
trate of silver. In the smalLedt capillaries, the cells are nar- 
row and elongated, or fiisifomi ; in the larger vessels, tbej 
are moi'e polygunal, with very irrcgtdnr borders. Tlie niu-lei 
which have been observed iu the walls of the vessels belong 
to this liiycr of epithelium. By the eamo jiroccis of utaining 
witli nitinto of silver, we frequently observe irregular, non- 
nucleated areae ; and it lias been supposed by some that these 
indiL-ate the preeence of stomata, or orifices in the walls of 
the vessels. This latter point, however, has not been posi- 
tively determined. It cannot at present be stated positively 
whether or not ortfiees normally exist iu the w^Us of the 
blood-vesFels; and the question of the passage of the cor- 
puscleH through the vascuhir coats is elill a iriatter of disens' 
eion. Most of tlu; anatomiwd points we have just mentioned 
have been developed by observations upon the Veseels of 
the frog. 

The diameter of the capillaries is generally as Bmall aSf 

the ajxe ai(nt ^encTAUj giv^-n In works upon microt«;opiciil ansl'imj-, £ul1i]ier 
reropiiiLW Hi** di^tinuliab ibiic we have mlopti-d, rogiirding as trut i!»|ilUarie« 
(ii)ly tlie tii.>kspU thni pn^ent buL a single coat. Tlic vcti:«L'U whii:1) bi.v>p mora 
than one cowl nre colli'tl by EiJlliker "arterinl or renous rc9»dB of tmblttloiL" 
(KuLUKER, Slimeitft d'Mflo/'^iffie fiumaiut, Tans, 19ft8, p, TflS.) 



rnrsioLooicAL 



OF THE CJ 



281 



or it raaj l>e smaller tlian that of the blood-coi^>ue[;les ; eo 
that tlicse bodies always move in a single liut;, and must 
hecome defoi-nied in passing througli the emallest vessels, 
recorering tlieir uatimil sbapct however, when thcj pa.sa into 
Tesaclfi of larger size. The cnpillarles are Binallest in the 
tent^iiR ftnil miUciiIar tiastie, retina, and patches of Pcyer, 
where they have r diameter of from xAir ^'^ Win "^^ ^" inch, 
In the inui.'Kjus hirer of the sJiin and iji thu inucoas mem- 
branes, they are from joVir ^^ jtVtt *''' '^" ^""^l' '" diamctt-r. 
They are l&tgest in the glands iind bonee, where they are 
f^'O'" a nVn to j-pVn of ^'i irieh in diameter.' Thcee niLnisure- 
nienta indicate the size of the vessels, and not their cahber. 
Taking out the thickness of their wnDs, it is only the very 
largest of tbera tliat will admit of the passage of n blood- 
dieU withii^ut a ehaugo in its furtu. 

UnHke the arteries, whieh grow smaller aB they branch, 
and the veins, which become larj^er, by union with eneU otliL-r, 
aa we follow the course of the blood, the capillaries form 
a true plexus of vessels of nearly uniform dlimietert brandl- 
ing and inosculating in evciy direction, and distributing 
blood to the parts, as their physiological necessities dciimnd. 
This inosculation 13 pccidlai' to these vessels, and the jilexus 
is. rif-h in tlio tissues, as a general rule, in proportion to the 
activity of thvir nutrition. Although their niTangementpre- 
BpntB certain ditl'erciu-es iu-ditferent organs, the capillary 
vessels Lave everywhere the samo general cbarautoristics, 
the most prominent of which are uniform difimeter and 
absencuof any positive direction. Thoiict-worb tlms Ibniied 
is Tcry rich in the Bubstance of the glands and in the organs 
of flbsor['>tion ; but the ves^icls arc only distended with blood 
during the- physiological activity of these parts.' la tbo 

• KaLLiKER, Sfiinxiitii iFM^o/offie /imnatni^, Paris, 1868, p. 771. 

'Thu irrungGment of tliu tBjiUUriiJs in dilTuruut ti^eucH «inJ orgiiDB hu 
Kenemllj been nKicnniutiJ l>y ntvuua <if mmutc inJGt.'tii)Eis. In aiudvuig 
iiyecCed prepBntiicin^, howcrtr, it njur^t bi- hamv in iriiud that the ikstio 
Bud yielding 7e•^lel3^ when urii&dull; iiy'ccted, we UHuallv distended to their 



282 



OIKCCLATION. 



lungs, Iho meslies are partifiilarly close. In other parts, 
the vessels arc not so abundant, presenting great ^'ariatione 
in different tisswefi. In the nnieclee ami nerves, in which 
nntritiuii is VC17 Motive, tLe supply is iiiucli more uliundant 
tbaii in otlier parts, like tibro-scrous niembnincs, tendons, etc 
In none of the tii^suea do we tind capillaries penetrntiiig the 
anatoniicAl elements, as the ultimate muscular or nervous 
fibres. Some tissues receive no blood, at least tlicy uonliiiu 
no VL-ssela wliicli are cupabltJ of carryin^^ rctl blood, and nro 
nourished by imbibition of the nutrient plaema of the i-Jrcu- 
lating fluid. Examples of theses wliich are willed extra-vas- 
cular tiBaucB, are cartilage, nails, and hair. 

Tho foregoing annttiniioal sketch gives an idea of how 
near the blood is brought to the tisisues in the capillary sys- 
tem, and how, once cunveyed thero by the arttries, and the 
Bup]i]y regulated by the motion of the muscular coat of tho 
snuiller veseele, the blood ifl distributed fo^r the purposea of 
nutritifin, eecretionj absorption, exhala-tiori, or M'liatever func- 
tion the part has to perforni. This will bo still more appar- 
ent when wo oonie to consider the course of the blooii in 
the capillaries, nnd the very groat eapaeity of this system, aa 
compared with the arteries or veins. 

The capacity of the CJipillary system h irumcnsc. It is 
only iieces&ary to consider tiie great vaeeularity of the skin, 
mucous membranes, or muBclca, to realize this fact. In 
injections of these parts, it seems, on niicroseopieal ei- 
fimination, as though thoy contained, nothing but eapIUo- 
ries. In preparations of tliis kind, the elastic and yielding 
coats of the capillaries are distended to their utmost limit. 
Under some cireuiustanfes, in health, thoy aro largely di*- 
tended willi blood, as the mucoue lining of the aliment- 

Utinotit FRpn«it,T, nnd tho capHIariox, therefore, occupy a space touch gnMtcr 
thnn Is ti:ituia1. In inji^tcd preparaiioitp of the Iiv^t, for (MSmplit, Iha Km( 
m-ifs of tli« nv^a BCf^ms (u be fornied of capUlurics ; nntL we are ^ ■ toaa to 
utidi-ret4iiiil, (It the flnt aiglit, how the ceUs, dueU, etc., flad pUcc bctwwB 
titcir meehet. 









r-Tj. . I 



.r :j- .. -_-— 1 r _ , • -t " t: . 



_ :r^ 









2§-t 



CIRCCLATION^ 



cfinio diiftiseil in tbe siil»etance of Ibe tissues, ]ikc a river flow- 
ing befwppii miinberless little islands, to be collected hy tlis 
vcmmB railiflca and conveyed to tlie lienrt. Apciimte niicro- 
Boopie;iI hivestigatious hnve now demoriBtnted the existence 
and given m ft cleat* Idea of tbe nQatijiiiy of the interme- 
diate vessels. In 1001^ the celebvateil Atiritomist, Kalpigbi, 
saw tiio movement of tbe bluud in the capillaries in tbo 
lungs of a frog. Since that time, pliyfii^ilogiBts have studied 
tbo etrculiitiun in various traiispareiit part^ in the iaferior 
atiimala, as tbe web of tbe frog's foot, the tongue of the 
frog, tlie Inngs of the frog and <if the wafer-newt, the niefi- 
cntery of veiT young rata or mice, the wing of tbe bat, etc.j 
and have minutely described tbe phenomena of tbe eirculn- 
tion as scon in tlieee situations. 

Tlie most convenient situation for tbe practical study of 
tbe capillary circulation is the tongue or the web of tbe frog. 
Ilore may be etndicd, not only tbe inovenient of tbe bbxid 
in the true capillaries, bnt tlie ctrculatitm in tbo smallest 
arteries and veiug, tbe vanaliona in caliber of these vessels, 
especially tbe arterioles, by tbe aiitiou of tijeir inuecnbir 
tunic, and, indeed, tbe action of vessels of considerabit) size. 
This has 'been a most valuable means of studyjug the circu- 
lation in the capillaries, as contrasted with tbe small arteries 
and veins; the only one, indeed, which could give us any 
definite idea of the action of these vessels. 

The magnificent spectacle of the capillary clrcnlation, 
as we have just stated, was first observed by Malpij^hi, in 
tbe Imigs, and aftei-ward by Lccuweuhoelt, Spallanzaui, Hal- 
ler, Cowjier, and uthers, in various parts. We see tbe ^cat 
arterial rivers, in which the blood tlows with wonderful ra- 
pidity, branching and subdividing, until tbe circulating fluid 
is brought to the nei-worlc of fine capillnries, where tbo tx>T- 
pueeles dsrt along one by one. The blood is then collected 
by the veins, and is carried in great currents to the heart. 
This cTtbibltinn, to the student of Nature, is of inexpressible 
grandeur; and onr admiration is not diminiahed when we 



OOCKBE- OF BLOOD VS THE OATILLAHIBB. 



2S5 



come to etadj the phenomena in detail. Wc find bore ft 
sLiIijeut afi interesting &s was the actitm of the hetirt when 
first Bccn liy Harvey, involving some of the most iin})orttint 
of the phenonaena of the yirculatiun. It vad he Been liuwr tlve 
arterioles reg^iilnlc the aupply of blood to the tissues; Ijiur 
the blood distrihutys iJeelf by the capillaries; and finally, 
having performed its ofticD, how it is collected and ctirricd 
off by the veins.' 

In studyitig the c-irciddtion under the microeeope, the 
anatomical divieion of the blood into coqutecles and :i clear 
plaeiim is observed. This is peculiarly evident in rold-bloixled 
HniHials, the corpuscles being coraparn lively large, and float- 
ing in a phisniii which forme a distinct layer next the walla 
of the voj^sel. The leucocytes, wliiuh are uiiiuli fewer th.au 
the rod corpuscles nrc generally found in the layer of plasma. 

In vessels of considerable size, as well as in some capilla- 
ries, the corpuscles, occnpying the centrill portlnli, muvc with 
'much giestcr rapidity than the rest of the bloud, leaviui^ a 
layer of clear plasnja at the sidee, wliicU is nciirly immovable. 
Thie. curious phenomenon is in tpbedfence to a phyfoit-al law 
regulating tho pas^nge of liquids throug-li capilhii-j* tubes lor 
which they have an attraction, snch fis exists, for example, 
between the blood and the vcasclu. In tubes reduced to n 
diftnieter niiproximating that of the capillaries, Ihe attiactive 
force exerted by their walls upon a liqtiid, causing it to enter 

' Varioufi mtllii>d? oC peepnring Lhe nnimal for exmiLiDAtiou liavi' !>«■« cm- 
ploTitfil. Tlnj one we hun'o fniuid mtiflt toiivfuicnt, in fxamining ilic (irmilaiion 
in (he IVoj;, b lo I'jrejik up tfar? niL-iLiillii wit1i n. □ce^dl^', an opi^iation nliich does 
oat interfere: niih the circulation, iiii^l (» nCtoch Ihe cin'miiil bj pias to A lliln 
[lifL-c of cork, slrc'teLiug ttio Wi-b uvcr an oriliuf in tbf ('ork, ami seniring it 
irltli pina t^rou^U thi< toes. Tlic lui'iulirBQC ia Ihcn mDiAtGne-d witli wntt^r anil 
coverwl with tlilu glusg, uiid, ir Uie gi peral surfBce be kept tiioIbI, llic circula- 
tion nmjf 1>B rtiidii^d Tor Iioiir?. By gi-Dily iudaiiug iho luiipj with a suiu]] 
blow.plpe-, B«4-'tirinjj tlie ulr by a lipilnre pulsed niound liii! laryrni btMiuatli tlie 
muL'iHi^ iB«mt>r&ni-, anii opi'iiini; lliu t'tiwl, tho ciriiulntl'jn may he^xjitnlncd in 
this aitinitioii. It ranv ]»? ruhjiihI in tbi? tonjnic (wbicti prcspntri a taiipj]Reent 
vien of iho circ'ilntiuii at well tiri of the ncrre!? nnd miificular filirea] by lirawlng 
il out ai the rDouth. nnd eprcailin^ it mto & ibiii ebeet, accuring It »iih pins. 
19 



2S6 



tlie tube to a certain distance, called capillary atlrnction, bo- 
comes an cJistacIe to the passage of fluid in obedience to 
pregBiire. Of course, as the diiimeter of tbc tsibu id rtMluced, 
this {area becomea relativelj inereaa«id, far a lai^r propor- 
tion of the liquid contents is brought m euntaet with it. 
When we coinc to the smnlleat arterips ami vc-iuis aiul etilt 
more the oa]>iIliiried, the capiJlai-j- attraction is sufficient to 
pro<luce the ininjovable layer, called the "atiU layer'* by 
inauy physiologiataj aud the liquid uu3y ujoves iu the centnil 
portion. Tho plasma occupies the position next the walls uf 
the vessels, fi.«- it is this ['ortion oi' the blood which ie cjipnble 
of wt'ttinfr the tubes. The traiie]uireiit layer was observed 
by Malpighi, Eallcr, and all who have described the capillary 
circulation, PoiseuiUe recoj^nized its true relation to the 
blood-current, and explained the pheuomonon of the etill 
layer by physical laws, which had been previously established 
with re^gard to the flyw of liquids iti tubeiof the diameter of 
from ij"! to 4 of an inch, but which lie had succeeded in apply- 
ing to tabes of the diameter of the capillaries.' 

A red corpuscle occiistonally becomes involved in the still 
layer, when it moves Blowiy, turning over and over, or even 
remains stationary for a time, until it is taken up agniu and 
carried alon^ with the central curreiit. A ft'W white corpua- 
cles are eoiistaiitly seen in this layer. They move along 
slowly, and apparently have a tendency to adhere to the 
avails of the vessel. This is due to the adhesive character of 
the surface of the white corpuscles as compared with the red, 
which can easily be observed in examining a drop of blood 
hctwoou glass surfaces, the j-ed corpuscle moving about with 
great facility, while the white have a tendency to adhere. 

Great differences exist in the character of the flow of 
blood in the three varieties of vessels which are under obser- 
vation. In the arterioles, which may he distinguished from 
the capillarit-s by their &ize and tlje [iresence of the miiseulur 

' PoiBBUlLLK, RteAtTrhta Mr ia CawM du ^■omenutilau Sang ihnt i» FeM- 



PHESOMEN-A OF THE CAPILLABY CmCULATIOS-. 



287 



and fibrous coats, the movement h distinctly remitteiit, even 
in tlieir most minute rams Beat ians. Tlie Llood moves in 
ttiein with much fjrcflter rapidity tlvan iti eiUier tlie cnpil- 
larios or veins. TLcj beeouie fiiualter aa tbvj biaucli, imd 
cany tlio hUiiid always in the direction of (lie cajjilliu'iea. 
The veins, wJiicli nre relatively larger than the artcri'es, cnny 
the liloud mure &tow3y, and in a etjutiniions btream, from the 
cftpillaries townrd the heart. In hoth tLeao vessels the cup- 
reiit is frequently wi rapid, that the form of the corpusctea 
cannot be distinguished. Only a portion of tho white oor' 
piiscles occupy the still layer, the rest being carried on ui the 
central current. 

Tbe cit'tiulation in the true capillaries is sui ff^^ri*. Here 
the blood ia di&tribute<l in every direction, in vessels of nearly 
uniform diameter. The vessels are generally eo small as to 
mluiit lull a &i!i^le row of eorjmsclesj ivhidi move almost like 
beings endowed with volition. In a single vesBel, a line of 
I'orpiiscles may bo fieen moving in outi direction at one mo- 
ment, and a few momenta alU'r taking a directly opixjeito 
Cfjurac, Spallanzani, ui one of hia observatiouSjdefioriliesthe 
following phenomenon. Two single rowsof cuquiscles, pase- 
ing in twu cnpillary vessela of equal size, were directed to- 
wartl a third capillaiy vessel, furmed by the union of the two 
others, wbicli ivoulil itself admit but a single corpusch". The 
c:oi*puseles in one of these vessels seemed to hold back until 
those from the otber had passed in, when they Ibllowed in their 
turn.' "When the circulation is natural, the movciut'iit in 
the.capLllarieB is always qnite alow conipai'ed with the move- 
ment in the arterioles, and ia continuous. Here, at last, the 
impulse of the heart ia lost. The eorpusclea do not neeea- 
sarily circulate iu all the capillaries which are in the field of 
■riew. Certain vasaela may not receive a cor|>uBcle for some 
time» but after a while one or two corpuecle-s become engaged 
in them, and a current ie fiaoily eatabliished. Many iuler- 
esting little points are noticed in examining the circulation 

' SpALLiJfiUP;, Etpsrimcti mr la OVtWtffi'Pn Paris, 1908, p, 1T7. 



CtRCULATTOH, 



for a length of time. A corpuscle ia frequently seen cauj»lit 
at the iniyle wliere Ji TH?ssel divkles into two, rcuialtiing fixed 
far a tiuic% diaturtwl and bent by tLe furci' of the current. 
Tt Bonn becomes relejieed, and, aa it enters the veerfel, regnins 
its originnl form. In some of the vessels of sinallost size, the 
corpuscles are sligbrly (kformed as they pass thronj;h. 

The scene is changed with every different part which 18 
examined. In the tongue, in addition tn tli^ artorinlee and 
reuales, with the rich net-work of capillaries., dark-bonJered 
nerre-fibres, striated muscular fibres, and pavement-ep it he- 
lium can Ite distinfjuifthed. In tlie hnifrs, the view is very 
beauttfid. Large, ))olygona] air-eelle are obi^erve*], bounded 
by capillary veseela^ in which the Korpn&cles move with ex- 
treme rapiility. It has been observed that the larger vessolj 
are crmrded to their utmost capacity with coqMiscles, leaving 
no still layer next the walli, such as ia seen in the cirtmlarion 
in other situatione. 

"When tlie ftrcuhttion has been for a ]ong time nndCT 
obeerratton, as the aninial beeom^s enfeebled, very interest- 
ing changes in the character of the flow of blood take place. 
The continuoufi &treani in the smallest vc&sels diminishca 
in rapidity, and after n while, when the contractions of the 
heart have become infrequent and feeble, the blood is nearly 
arrested, even in the fimnllest capillaries^ during the intervals 
of tJie heart's action, nnd the cnrrent becomes remittent, 
Ab the central organ becomes more and more enfee!ded, the 
circ^nlation becomes interunttent : the blood receiving an 
inipnke ftotn each contraction, bnt remaining sJalionarj- 
during the inteTvaU. At this time, the corpuscles cease to 
occupy exclusively the wtitr:d purtiun of the vessels, and the 
clear layer of plasma next their walls, which was ob- 
Berred in the normal circulation, is no longer a|*pnrent. 
Following this, there is actual oscillation in the 'capilhirics. 
At each contraction of the heart, the blood is forced onwnni 
a little distance, but atmoat immediately returns to about ila 
former jiosition. This phenomenon has long been observed. 



E.VPIDITY OF niE CAPILLARY CIKCULATION. 289 

is esrplairted m the I'ollowtnj!; wdj' : As tlie lioait lias 
le eniecliled, tlie contmcttoMs iirc bo intrequcrit and in- 
effectual, that (lurloi; their intcrvnl^ tlie eoD9ta.rjt flow in tho 
eiLpillaries is entirely tirrestetl ; fur tljc iirtwiul preasiire, which 
h its iniuieiliiite cause, and whicli is tiiaiutained by tliu stic- 
ceefetve cliiLr^c^ of hloud scut into the arteries at each veiitnc- 
ular systole, ia lost. But aa the IjIockI is cuntained in a coa- 
iii!eted systoiii ol'ijlciaed tubes, the feeble iinjtulse of the heart 
is propjigsitetl through the vessek and pi-uduiT's a uliglit im- 
pulse, oven ill the smallest capillaries, whii^i dilates them 
and forces the fluid a little distance. As soon, however, as 
tliiG heast ceases ti> contract, the uorreut ii arrested, and the 
blood, meeting with a certain amount of obstruction from tlie 
fluid in tho email veins, wliidi are still farlher reirioved from 
the heart, is luady ti> return to its i'i>rmer pusitiou. 

This phenomenon contiDuea for a abort time only, for the 
heart eoou Iobbb its contractility, aud the circulation in all the 
veasela is permanently arrested. 

liapidittj of the Cifp'Tlary Circuht'&n, — The circulation 
in tlie c-apJUai'ies of a part 13 subject to such great variation?, 
and the differences in different situations are so coiLsidcrable, 
that it is itiipossible to give any definite rata which will 
represent tiie ra|)idity of the capillary cireuhdion. It is for 
this reason that it has been found tin practicable to estimate 
tiie capacity of rhe capillary, as compared with the arterial, 
systetn. The rapidity of the flow of blood is by no meaita 
aa great aa it appeal's in microscopic esaminQtions; bebjg, 
of Course, exaggerated in proportion to the magnityiug power 
employed. It is, nevertbelc?*, to mici*oscopie iiivestlgationa 
tliat we ai*e iiKk-btt^d fur tb<? scanty inltii'mattou wo possess 
on this subject. The estimates which have been made by 
Tarioua observerfi refer generally to cold-bictoded aniniats, and 
have been ajTived at by eiuiply calculating tlie tiuie occnpied 
by a blood-corpiiacde in pausing over a certain distance. Hales, 
who was the first to investigate this question, estimated that 



aao 



dBCn-ATIOX, 



in llie fi"ocj a L'orpiiscle moved at the rate of an incli in ninetj 
secomls.' Tlie petiumtea uC Weber and Valentin are coo- 
BidorQlily higher, behig about -^'^ of an inch per second. 
Vollcnumn oaleiilated tlie rapidity in t)ie ine^ntery of the 
dog, which would apprnximate more nearly to the hflnian 
eulijeci, and fouiHl it to be about -^ of au inch i*r second.' 
TierOrdt made a uiniiber of curitnis ob&ervHtiona upon bim- 
eelf, \>y which he pi-ofessed to be able to eetiinate the rapidity 
nf the fb'unlatiou ill the little vessels of the eye. lit; states 
that when tlie eye ifi fatigued, and sometiines when the ner- 
vous system is diRordered, compression of the globe in a cer- 
tain way will enable one ti» see a current lifce that in a capil- 
lary plexus. This he believes to be the capilhiry cimulation, 
and by certain calculations he formed an estimate of its rapid- 
ity, puttiug it at from ^'i^ to jV of an inch. The latter figure 
accords pretty neflj-ly with the observatioiifl of Volknmnn 
upon the dog.' IIow far these observations are to be relied 
upon It ib impossible tu say, Certainly no yrcat iin|M»rtJince 
would be attached to them if they did not, in their results, 
approximate tu the e&tiraiiteB of Volkmann^ which pnjbaMy 
represent, more nearly than any, the mpidity in the capil- 
lariea of the huitiau subject. 

After what has been said of the Tariations in the capillary 
circulation, it ta evident that the foregoing estimate* are by 
no means to be considered exact. 



Bdatioun of the C^ipHiuri/ Circulation to Jie»i»iT€itlQn. — 
In treating of the iuflueiicc of respiration upon the action of 
the heai-t, the arterial pressure, pulse, etc., it Inti already 
been stated that non-aorated blood cannot circtdate trecly in 
the capilliii'ies. YHrion& ideas with recant tit the effects of 
asjihyxia upon the circulation have bt'en advanced, which 
will he again diecussed iji connection with respiration. The 

• BUttii^ Smaifi. eoniahti/tff IfigattutaHeJcM^ Xondon, ITflS, p. (M. 

' Mit.^&Eun AiiDS, Iiipint Mr la J'h^i'jiajjU, Vmi, I BBS, lome 3f., p. SM 

•Ibid. 



RELATION'S TO EESPITtATIOy, 



2&1 



fact ta eviJeiil:, that arrest of respiration produv^es arrest of 
circulation. This id oriiiuiinly attriljuted to an irnpeflinient 
to the pftfssage of Wood tlirough the lunga, wlien tliey no 
longer contain the proper qnanrity of oxygen. This view is 
entinjly theoTetitjiil, and has been dieprwed hy ex]ierimeiit9 
dating more tliau lialf a centary ago. In 1789. Goodwyu 
ailvanct'd the tlieury that, m asphyxi«, the bluod paseea 
tlu-uugk Hie lunge, but js infapablo of exciting contract iona 
in tbo letl ventrit-le,' Ciebat, in hie celebruted essay ■" Sur 
la Yi^ ei la Mort,"^^ 1805, proved by experiment tbiit blauk 
blood passes througli the lungs in aspliyxiii, and is Ibniid in 
the arleriee. His theory wna tb«t iion-ai'rated blood, ciri?n- 
lating in the papillfiries of the nervous centres, arrests their 
iunctii)n, Ihna ticting indirectly ujxin the circulation; and 
that iiaally the heart itself isi paralyzed by tho circulutron of 
black blood in its Bubstance. 

Dr. John Keid, in an article '*0n the Cepsntion of the 
Vital At^tious In Asphjiin," ' describes an experiment in ivbich 
aha-TriHdynamometer iippltetl to the fennjral artery of a dog 
indieateiJ tncrense in the arterial jiressure duj'ing the first 
moments of aspbysisi, followed (iiiatly by a depreBsion in the 
mercnry. He found a corresponding diminution iu the 
prefisure in tho vein of the opposite side. " Thie was so un- 
loolied for — at tirst siglit so inexplicable, and so niiieh at 
variance with my preconceived notious on the suhject," eaye 
the author, " that I was strongly inclined to believe there 
must be &onie source of fallacy ; but alter repeating the ex- 
periment more than twenty times, aud invariably with the 
same reaults, I was at last compelled to admit its apcurncy.'' 
Thia he Buruiises is due to " an impediment to the jia^t^age of 
the venous blood through the capillaries of the ajstemic cir- 
culation." In hifl conclusions at the end of the ariicle, how- 

' P. BiRAW, Caar* iSt Phitivta^e fait d la Jant/W A Metlteitic ilt I'arU, 
IbSl, loniK; iii., i>. 414, 

' Jons Run, M. D., PhjfukJiirikitl, Anaiomiral, a»il l^ii/aJoffiraf Hi^trayft'tt, 
BiJinliurgli, 1S48, p, £fi. (Arlide extracted fixjiu the £tiinfinrifh JMimI and 
Sttrgieal Joumai, April, 18-11,] 



293 



crncuLATios. 



ever, lio takes no aceonnt f>f the I'csulta of this experiment, 
wliicii point cottclusiTelv to nrrest of blood io the cftpillar)' 
arsteifi, and the contrlueiona with regard to tlie effect of a»- 
pbysia upon the circulation are fiubetiintiallj tlioeo of Bieliat. 

Tiie tiiiiuc"diiito eftecEs of asphjr'xia upon tlic circulation 
are referable to the general ea[)iirary system^ This faft was 
domonstrated by experiments nn the frog publislieiJ in 1857.' 
lu tiieae esiienriientSj, the medalla oblongata was brukeu 
lip, aud the web of the fuot stibinitted to microscopic exam- 
ination, Tbia o^wration does not interfere ivitli the circiiU- 
tion, which may be observed for hom^ without dit^icultj'. 
The cutsTieoua surface was then coated witL collodion, care 
oniy being taken tu avoid the web under obficrvatioii. Tlie 
eflect ou the cirdulation waa iicimediate. It inetantlj? be- 
came less rapid, until, at the expiration of twentv luinntt*, 
it bad entirely ceased. The entire coating of collodion waa 
then instantly peeled off. Quite a rapid circulation imme- 
diately commenced, hut it soon began to decline, imd in 
twenty minutes bad almost ceased. In another obfiervatjon, 
the contlng of ci'lMion was a-pplied without destroying the 
incdnlja. The circLilatioii was aii'ected in the Same manner 
ad hefui"e, aud ceased iu twcuty-five minutes. 

These experiments, taken in t'onuection witb obaerralions 
on the influence of anpliyxia upon the arteria! pressure, con- 
clujiively show that non-aeralcd blood cannot circulate freely 
in the ayatoniic capillaries.* Venous hlood, however, can !» 
forced through them with a syringe, and even in agpliysia it 
filters slowly througb, and if air be admitted to the lung* 
before the boait has lost its contractility, the circulation is 
restored. 

No difEereuccs iu tiie capillaiy circnlation have been no- 



' Sue iLrUu'lo by l1'« autlior, cniltltMl "Pticaumcim of tli« CaEiilliirj' CLruult- 
tion," American. Juu-riud nf At MefUeal S^eneet, July, 18H'?. 

' In theae cspmuienls, ether Kad preriou'ly been freely •pjtlidl to ihc surface 
to KtiikT it 4».TU>iii that lUe cFteCs QQ the (ircuUiioci were not tke i-muIi of ihu 
mgwiUcnt of Ih'C ratlodioiL 



CA.PSE8 01? THE CAI'U.LAUV CIKCCLATiaN, 293 

tiGe<] necoiiipanviog tbe ordinary acU of loepiration and 
expiration. 

Cavscn of the Ciipilkiry Circulation, — TLe con traction a 
of tlie k'ft ventnL'Ie are evidently t'HpaMe of" glring an im- 
palse to tlio blood ia the Bmalleat arterioles, for a marked ac- 
celeration of the current accompanying each systole can bo 
dUttnguiAlwid in all but tlio true capillaries. It has alsy been 
ehown by eX|)erirnentB after death, that blood can be forced 
tliroiigli tlie eapillary system and returned by the vcitis oy a, 
force less tban that exerted by the heart. This, howevpr, 
cannot ri^dly be applied to the natural cii-culatinn, as the 
aniallest arteries are endowed during life with otmtractilityj 
which is capable of modifying the blood ciutpdI." Dr. 
Sharpey adapted a syringe, with a lupmadynamonietor at- 
tached, to the aorta of a dog just killed, and found thnt fresh 
dofihrinated blood conld be uiadc to pass through the double 
capiiliiry syfitems of the intestines and livor, by a jtrcseu^e of 
tliree and a half inches of mercury. It spnrtcd out at the 
vein in a full jet under a pressure of five iucheB, In this ob- 
tervatioiij the aorta was tied just above the renal arteries. 
The same ivressui-e, the ligature being removed, forced the 
blood through the capillaries of the inferior ejctremities.* 
This is much less than the arterial prcsbure, which ia equal 
to from five and a half to sis iiichea of mercury. 

It is thua seen that the pressure in the arteries which 
forces the blood toward tlie capillaries is competent, unless 
oppoBod by esceseive wotraction of the arterioles, not ODly to 
cause the blood to eiiHiiilote iu these vessek, but to return it to 
the heart by the veins. This fact is so evident, that it is un- 

* Xh chowing Van iJiOcrencv^ between tbe vcascla iiunmiiutclj' iLfler doiitli, bhiI 
ailer tlie v hnve lonl H.II tlicir vilul prci[R'Cli(!d, wo mil)' rvCi^i to uu Db^erriLtioa uf 
B^rvt! (ly'i Lif., (I. 776), in wliu"!! !jii foiirit] It ErapoBsiblc lo ii\j*^ct, willi u eolidlfl- 
Blile Kiiid, ^uti uf iLb buily iiii'rii^UiituI; ttltur amputtitioit Wftter paesetj with 
ftu^t^, bill alcoli-ul or viDeunr coiiliJ uol lit; furctnl ihramglL 

* Twuu unil iiowMAS, The r/tsitoiotfieii-f Artalvriiif anJ Fh;)siohff^ o/ .l/iin, 
Pb&adclpliifl, 180T, p. HIS. 



2M 



OlKOtrLATIOX, 



neflessitr}- to (lisfU-sa the views of Bicliat, ami Minie citliew, 
wlio aiijipusieLt rlint tlte action ol'tlie licart-hml no eff»;ct njwji 
tlio capillarv circulation. It must be admitted that this is its 
prime cnii?e; fliid the oiil}- questions to be considered are, 
tij-st, wlietber tLere be any reEWou wLy tlie fort-e of tlie heart 
should not operate on the bloud in the capllianes, oiid 
eeeoud, frliether there be any force in these veasela which 
is sniieraddenl to (Ite action of the heart. 

The tirdt of thuae questions is answered by microscopic 
ob&ei-vatiuiis un the Kircnlation. A distinct impulse, follow- 
iijg each ventricular systole, is observed in the smallest ar- 
teries. The blood flows from tliein directly and freely into 
the ciipillnries; and there is not the slightest ground for the 
Buppositioii that the forae la not propagated to this ^ygtcm of 
vessels. 

Various writers have silpposed the existence of a " capil- 
lary poMer," which they have regarded as of greater or IcfiO 
importance in producing tho capillary circulation. The 
viewfl of some are purely thooreticiiil, hut others base theJr 
opinion on microscopic obscrvationa. These views do not 
demand an extended diseuesion. Tliere is a force in opera- 
tion, the action of the hettrt, which is capable of prodUicing 
the cftpilliiry circulation ; and there is nothing in the phenom- 
ena of tiie clrcnljitiou in these vessvU, which is inconsistent 
with its full operation. Under these circumstances, it is 
mi philosophical to invoice the aid of the currents produced 
ill eapillaiy tubes in which liquids of difiereut cliaractere are 
brougtit in contact, or a " capillary power " dependent upon 
a vital nutritive attraction between the tissues and the blood, 
mdetfl we do it on the Utsis of phenomena observed in the 
eapillariBa when the action of tlie heart is suppressed, 
'Wlien rbe heart ceiL'^L-a lis action, movements in the 
capillaries are somctiotes due to the contractions of the ar- 
leriefi, a jToperty which has already been fully considered. 
Movements which have been observed in nieinlirflues de- 
tached tjoiu. tJie body are doe to the mere emptying of the 



CAUSES OF THE CAPILLAEV CIKCfLATION. 



295 



diritled vessels or &im]>le gravitation. It niuflt bo remem- 
bered ttiat in microscopic examinations, the tnoveraL'nts ;yhich 
are obserretl are immenaoly exaggerated bv tlie maguitying 
pOM'er, and we receive, at lirst sight, an eiTintieQ'tii* iOea of 
tlicir rapidity. Tho movenicnts of tlits bluod in dotached 
mecnliranea, due merely to graTity, liave been eo satisfactorily 
explained by the cxpcrimeuls of Poiseuille, tliat it is deemod 
nnnecessQiy to refer to the ohseiTatioaa of thuae wlio have 
ftltrlbuted this phenomeaon to other causes.' 

Dr. Dowler, of New Oi-leatie, made some exporimenta on 
the circulation in patients dead with yellow fever, iu which 
lie found that the tluod wouhi flow in a tolerably full stream 
fi^am a punctured vein a few mimitea after death. This ho 
Ottributes to an indepeiidout action of the capillaries, which 
continues for a time nfter the action of the heart has 
ceased.'^ These oliayrvatioutt are met by the following experi- 
ment pc?rfi>rinc'd years before by Magendie,' A ligature was 
passed around the Ihl^jh of a dog, leaving' only tho eniral 
artery and vein. A ligature was then applied to the vein, 
BTid a small o}jeiiirig made below it in the vessel, from which 
the hiood escaped in a JL't. On compressing the artery, the 
flow of blood was not immediately arrested in the vein, but 
contiuued to gradnally diminish in force until it stopped after 
a fpM' moments. On exmuining the artery below the point 
of compression, it was Ibnnd contracted, and completely 
emptied of Idood, while the vein was full beluw the pnno 
The pressure bting removed from the arteiy, the blood 

uiienced to fiow from the vein, and a jet was toon estab- 
liabed as before. IVlien tfie artery was slii^htly compreBsei], 
30 aa to allow the passage of a small quantity of blood, not 
enough to distend the vessel, the blood flowed from the vein, 
bat no longer In a jet. This experiment bIioh-s that when 



* P0I3ECIU.B, }leefierehf*mF tir» CitMen <iv ifoufenient (At Saufrdtini la Vait 
•MM C'ipifltifi*, 1886, p. 127. 

* Di;X(i [,t:wN, Human I'/rgjiuhffff, r):]la(3elphla, ISSl, vol. i., p. iW 

* liAOUinE, /Veru £Umeritaire de Phj/tiof'^e, Tana, ISSS, toiud it, p. 8 W. 



2^G 



cmcrLATioN. 



an arfery fiupplyitig a piirt with bloijcl is removed from tl<e 
inflnenee of the LeHrt» the vessel ■vrill contraet and force its 
contents into tbo vein. Thia sflbrda tSie mo&t rational explti- 
uation ut' tlie plienoaiena ob&erveJ by Dr. Dowk-r. "Wlieu 
the Mood is allowed to enter slowly, &o as iii>t to distend tlio 
vessel, though it be supplied to the uapillary system^ it does 
not there undergo any propelling inflnence, eorapetent, at any 
time, to iucreiise the rapidity ol" the flow from ihu vt'iu. 

Phyeiologiata who, like Biehat,' have been niiable to 
explain the local variations in the capillary circulation with- 
out the jiiterventiou of a force resident in these vesiels or tlie 
anri-oimdiug tisauee, have not appredated the action of tlie 
arterioles. These little vessehi are endowed to au eminent 
degree with contractility and, by the con tract ions and rc^ 
laxationB of their mndcuhir walls, regulate the supply of blood 
to the capillaries of individual parts. Their aHicni »* cww- 
jxif&jif. fojiroduce all tho carrathns ich'/oh are oifscrved in the 
cuj/iUttri/ circulation. 

It i& evident, then, that the arterial pi-essure, which ia 
itself derived, fi-otn the action of the heart, is comi'etent to 
produce the circulation of the bloody as we oheei-ve it, with 
all its voriatione, in the capillary ves&ela; that there is no 
evideDce of the intervention of any other force, but, on the 
contrary, mioroacopic observationa and a\i>erinjenls on the 
arteries and velna, thua far, show that there is. no otlior force 
itt operation,' 



* IL haa been ue^ctcd thnt there ii n clTCulation of [h« blood in tlif^ irec >■«■ 
ei3lns&, the firaC blood-vcs9f Id tlint atv icvAoyivA. bofurG thA bcnrC is funned ; bat 
there arc nO dcfinlto nnil ri'liublc nliaerrntiiiD^ wLicli aliOn thai there is ■nj' ngulaP 
ii]i)TcQi(.'nt of the blooil, nlik'b ran \k likciit'r] |ij tlje uti^uktlnn as ii is ob«ef-f«4 
■£U;r the dL'vdopm<-Dt of Ihn Ueart, anli-noc lo the n[ifieatntice of a contmutihg 
ci-nCrnI urgnn. Aii.i)tliur csnnipltr ol' vhiit ii suiijxjsoil to be I'irculaljuii oitllOUt 
the iaLcrvijaliut) of thu huart is »i tiisca uf ncanliac fiulus^s. Muoalvra without it. 
btinri, trliii:U bar? um^crgoiK; wn^iOcrobtt.' Uerrlopmetit and which prtMont vfStxtoM 
of uilL'i'im, cuijillnriud, auti vdiu, huVD hova ilcscribed, A31 of thcde, hoMerpr, 
uv ucwuipBuied bj* a IaIh, in wlikti the dcvcloptaent of the cLrcnlutorj sj-sU-in U 



ISFLrENCE OF TEMPEBATUBB. 



S97 



Tiifuence of Temperature on the CajpUiary i trculativn. — 
Within moderate limite, a low temjiorature, iuducctl bv local 
a]»ljlicatii]Us, liasbt^cn found to diminish tLe quantity of blood 
seut to tlie capillariesj and rL-tnrd the dreulation ; while a 
Iiigli tem]ji?rfitnre iiirreases the supply of blood and aL-eoler- 
ates ila ciirreut. The niet'lianisru of tliis is beautifully shown 
by the esperiiiieiits of PoifjeuiMe. Tliis observer found tbat 
vheii piece of ico wop. applied to (lis web of a frog's foot, 
tbo mesentery of a small ■wnrni -blooded atumal, or auy part 
in wUicb tbo cftpilUry circiilatloa can be obserj'cd, tlie qunn- 
tity of corjiusules circulating in the arterioles became vory 
mncU diuiiiiisbod, "tbose M-liich carried two oi* throe rows 
of corpiiseles giving paB8a»;e to but a single row." The cir- 
eulfttioTi in tlie capillaries first became slower, and then en- 
tirely eeased iii parte. On removing the ice, in a verj' few 
minutes the cii'CTilation regained its former cbariactera, 

If, on the other hand, the part be eovi.'ri>d'witli water at 
104°, tbe rapidity of the current iu the capillaries is so much 



perfect the moat rcuiark&b1o i:a£c of ttii^ kiaJ la one reported hj Dr. HoustOD 
in the DuttHn Jf/urnal nf Med'ieal Sciener (1836, Tol. i., p. 2M). In Ibia Ciiae 
tbci* *bs ft perfcft twin, but two distinct eonJa and scla eT luembraueS. Dr. 
HoiistoB sujijwsed Ihdt Ibe circulation in tUb mouster was caniod on by "capil- 
lary poKtsr" nliwo, la tbr«c citacs, a» L.aa been shn-nn bj AatlL-j Cooper and 
Xjillivm^gd {&liiil'NFffh J/riiitvj/ and Sarglcnl JuUTnal^ ISi-l, r^il, Ixii,, p. IBA ti 
«'/.), tJj«w IB a free apRstoEioeis oT tbe veaseJ* of ihe two flatuses ia Uio plncenU. 
Bume hicve EUpposed, frocn the faet ihnt tbu siims of t!iL' tDOUsUrurD uot provideil 
will) vnl?*^, tlittt in it tlie circulation fe from tlie vciad tu (lie iwlcrii-a, urie inverted. 
Ilia nut exuctl; ukur havr the dTeiilAlion ia carrioil ou in on aeardiae ftttus, 0n- 
flo'ilittiilly t.h« lienrt of one child may influeneL- tbe flrcukttion in ilic nuiliilieol 
i-.'e*pIs of ibe oHw-r, ib cuSM of twind ; for LuUtmaiid has obsciTcd {toe. eit.), aficr 
llie biitb of one pWlii, the cord liaviag becti tlividcd, & rc|;ular pnl^mlik flow from 
Hid plttPenUl eititmitj of llic conl, oa from A dmJcd ortery ; but we find icm 
eur^ful eiacuicatioQ of tbe cas« n-ported by Dr. IIoiiaIoq, and au urticle On tha 
TOjsc bj Dr, G, ChlvDrt Ilulluid {Edinlnirffh AM. and ftirp. Journal, loe, al.), nO 
SulBeient evitJetiee ibnt tbc circulBliou wns eurrie«l on by any " capiUury povrer.'* 
Not IxiiTi^ able (o re;^rd as facte tlicae groundi*, on ffhiclL some lt?^e based (heir 
lielief in Ihe eristeiice of a fore<i in tiic tirculatioii vhlvh b iiideiMjndetit of tha 
btmrt'ti u^tLOfl, vt liave abBtuiued frrna tbdr diacu^^ion iu Li'eatlnj; of the cauaca 
of Lhe cttpUlal'; ctrculaiiou. 



CmCDLATIOH. 

increased, tliat we cau hardly distinguish the fonn of the 
corpuscles. ' 

Influence of Direct Irritation upon the Capillary Circu- 
lation. — Experimental researchea on the effects of direct irri- 
tation of the capillaries, in parts where the cirealation can 
he ohserved microscopically, have been qnite numerons since 
Thompson studied the effects of saline solutions on the web 
of the frog's foot in ]813.' The most noticeable papers on 
this subject are those of Dr. Wilson Philip ' and Mr. Wharton 
Jones.* The latter paper, which received the Astley Cooper 
prize for 1850, is based on very extended and carefuUy- 
conducted observations, in wJiich the author, by means of 
various irritants, succeeded in producing very curious and 
interesting phenomena, which he regarded as inflammatory. 
It is not our object to discuss the nature of inflammation, or 
to treat of the changes in tlie character of the capillary circu- 
lation which are supposed to attend this condition, as this 
subject is eminently pathological ; but it must be remember- 
ed, in considering the effects of direct irritation on the capil- 
lary circulation, that the phenomena thus observed in cold- 
blooded animals cannot be taken aa absolutely repi-esenting 
the characters of inflammation in the human subject. When 
an irritation is applied to a transparent part, the phenomena 
observed may be due to many causes, as the direct effects 
u]>on the contnictilc elements of the blood-vessels, the reflex 
action through the nervous system, and the direct influence 
of the application upon the constitution of the blood. Saline 
or other fluids are competent to modify, to a very consider- 
able extent, the composition of the blood, separated from it 
only by the thin, permeable walls of the vessels ; and the 

' FoiHEUiLLE, op, cil., p. I5S ft »«q. 

' TnoMi^os, Ledum on InfiammaHoa, Edinburgh, 1818. 

' Medico-Chirurffical Trarmaftiont, 1823, vol, lii. 

* Guy't Hospital Reports, vol. Tii,, 1851, On Ou SlaU of lAt Blood and tAt 
Blood-vanh in Infianuiiation, atceriained by Expcrimentt, Jtyeetionty and Oitta^ 
joiion* by the JficroMeopt, by T. Wharton Jo.ses, F. R. 8. 



INFLCESCE OF IKKITATIOX. 299 

phenomena which follow their apiilication arc necessarily 
very cocuplcx. The process of iuflamination is by no means 
completely understood, but it is pretty generally aeknuwl- 
edged to be a modification of nutrition, in a way that we are 
as yet ignorant of. "We are hardly prepared to admit that 
this modification, whatever it may be, can be induced under 
our very eyes, simply by the api)Iieatiou of irritants. "With 
these views, microscopic researches on the " state of the blood 
and blood-vessels in inflammation" do not asgnme the im- 
portance which is attributed to them by many authors. 

Keeping this in mitid, we may state the following as a 
summary of the phenomena which have been observed in 
tlie capillary circulatioo, as the result of irritation a[)plied to 
transparent parts : 

The application of the irritant is immediately followed by 
constriction of the arterioles, and diminution in the rapidity 
of the current in them as well as in the capillaries. 

This constriction of the vessels is but momcntarj', if a 
powerful irritant, like a very strong sttlution of salt, be used. 
"ft is followed by a dilatation of the vessels, and an increase in 
tto rapidity of the circulation. 

Soon after the vessels have become dilated, tlie rapidity 
**'" the circulation is progressively diniiniBlied, until oscillation 
**■ 't^l'xe blood in the vessels takes place, wliich occurs when 
ta© ciireulation is about to oense. This oscillation Jinally 
8^'^'^sa place to complete stiignation. Tlie vessels become 
'*''** ■^V'^Jed with blood, so that the tr!insi»arcnt layer next 
^^^^K" walls is no longer observed. In this condition, it has 
, ^*». often noticed that the projwrtion of culorlcss cor|mricles 
" ^^icsreased. 

^^ollowing the contraction and subsequent dilatation of the 

®**«ls, there is stasis, and engorgument of the parts which 

. "^^ been exposed to irritation. If the irritation he diacon- 

^***ed, ibis condition is gradually relieved, and tlie blood re- 

**^^8 its normal current. 

IjQ inflammation, as it is obser\ed in the conjunctiva and 



300 CIRCULATION. 

other vascular parts, there is uiiquestionahly congestion of tlie 
vessels; hut there is no positive evidence of stagnation of 
hlood in the parts as a constant occurrence. The circula- 
tion seems, indeed, to be more active than in health. With 
regard to the microscopic phenomena just mentioned, the 
contraction of tlio arterioles is simply the effect of a stimulus 
upon their mascular coats; and dilatation takes place prob- 
ably in consequence of the excessive contraction, tor it has 
been shown that this condition of the muscular fibres is pretty 
constantly followed by unusual relaxation. It has never yet 
been determined how far the stasis of the blood is due to an 
osmotic action of solutions employed in observations of this 
kind. 



CHAPTER Vm. 

CrECULAnON OF TEE BLOOD IN THE TEISB. 

Physiological imBtoniy of the ymds — Strength of Ihe coiita of Ihe yolns— Tiil^M 
of cite viAas — CoiirSL' of tins blood in the veins — Prcfleutc of blood io ibfl 
viuiu — Rapiility of the Tcnutie ciri'iilaiion — CauHes of the venous circulalioci — 
Inlliienee of muscular coiilniciiO'ti — .lir io ihe vtias — Function of tLc vitifoe — 
Venous anoAtomoaL's — Coniiltions nliicli impctlc the iijnotia circul&tJtjn — Re- 
gurgiUnC vesoiu pulse. 



Phygiolotjical Anatomy of the Yeins. — The blood, dis- 
tributed to the capillaries of all tUe tissuea and organs bjtbe 
arterits, is collected from these parts in tho vcliib aud carried 
back to the heart. In Btuilying tlie aiiatowiy of the capillary 
ByBtem, or in observing the passage of the blood from the 
capUkries to larger veseeU, in parte of the livjtig organism 
nbich can be Bulituittcd to micru&copic exaniination, it la 
Been that the capillaries, yessela of nearly xioiform diameter 
and aaaetomo^ing in every direction, give origin, bo to epeak, 
to a system of vessels, whidi, by miitm with othera as we fol- 
low their conree, become larger and larger, and carry the 
blood away in a uniform current These are called the 
venules, or venona radicles. They are the peripheral railieles 
of the numerous vessels which transport the blood, after it 
has served the purposes of nutritEon or secretion, to the cen- 
tral organ. 

The venous system may be considered, in general terras, 

as divided into two Beta of vessels : oucj which is deer, aud 
20 



30S 



CIBCULATION. 



Bitiiaterl in proximity to the arteries; and tlie other, whic 
is Bujierfit^a], and rewives for the most part the blood from^ 
the c-ulaneoHS surface. The entire capacity of these yessels, 
as compnred with the arteriesj ia very great Aa a general 
rule, eac'l] vein when fiiUy distended is larger than its adja- 
CLMit artery. Msiiiy arteries nre accompanied by twu veins, 
ae the arteries of the estremities ; while certain of them, like 
the brachial or spermatic, have more than two. Added to 
thest! ia the superticial sj'steui of veins which have no corre- 
sponding arteriea. It ia true that Bome arteries have no cor- 
responding veinsj hnt examples of this kind are not siitfieient- 
ly mimerons to diminish, in aiiy marked degree, thij j^r^at 
preponderance of the veins, both in number and volume. It 
is impossible to give an accurate estimate ot" the exlreioe car- 
paeity of the veLnn ua eocnparud with the arteries; but from' 
the beat information we have, it ifl several times greater. 
Borelli cBtimatc'd that the eajiacity of the veins was, to the 
capacity of the arteries, aa 4 to 1 ; and Ilailer, ati SJ to 1. 
The proportion is very variable in ditierent parts of the body. 
In some situations the capacity of the veins and arteries ii 
about efjnal; while in others, aa in the pia mat^, accorJiug 
to the researehefl of Hirsehf^ld, the veiae will contain six 
times as amch as the arteries.' 

In attempting to compare the quantity of blood normally 
circulating in the veins, wiih tliat contained in the arterit*, 
such variations in the venous eystem at ditferent times and 
in different parts, both in the quantity of blood, rapidity of 
circulation, pressure, etc, are found, that a definite estimate 
is impossible. It would be unphilosophical to attempt im 
approximate comparison, as the variations in the venous cir- 
oulatiou constitute one of its greatest and moat important 
phyeiologicol pt^culiaritiea, which must Ije fully appreciated 
in order to form a just idea of the function of the veins. 

' E^IULKD, Court di J*htMialoffi/t, Paris, 1855, lome if., p. 7, The drrulalinn 
In tliL' erectile iLmufH will bo sepiLralvly cmi^iJen-J, and no kccoutil U now ukva 
uf iho rtlttivc Cutudty q( vdna and txicaea in thetL, 



PS'raiOLOOICAL AVATOUT OF THB TSIIT8. 



303 



Tl 10 arteries are always full, and their tension is snbjoct to 
[jomparatlvely sHglit variations, Folloiving the Ijlood into 
the capillaries, there are tlio iminenso vaiiationa in the circn- 
latioB with varying physiological conditions of the parts, 
■wiiich we have already noted. As would naturaSly be ex- 
pected, the condition of the veins varies witli the chaiigos in 
the capillaries, from which the blood is taken. In addition 
to thie, there are indepeiidont variatiouB, ae in the erectile 
tissnes, in the veins of the alimeutary canal diiripg absorp- 
tion, in. veins subject to pressure, etc. 

Following the veins in their coiiree, it is observed fhat 
anastomoeea with each other form the rule, and not the 
exception, as in the arteries. There are alwaja a nuniher of 
channels by whiuh the blood may ho returned from a part ; 
and if one vessel be obstructed from any cause, the eurrent 
ifi simply diverted into another. The vetua do not pre&cnt a 
true anastomosing plexus, such as existe in the capillary sys- 
tem, bnt simply an arrangement l>y which the blood ean 
easily tiud its way back to the heart, ami hy which the vea- 
eels may accommodate themselves to the imnieaae \*wiations 
in the qaiantity of tinid contents to which they are liable. 
This, with the pecnllar valvular arrangement in all but the 
veins of the cavities, provides, against obstruction to the flow 
of blood through, as well as from, the capIllarieB, in whicli 
it seems essential to the ]>mper nutrition and function of 
parts, that the quantity and course of the blood should be 
regulated exclusively through the arterial eystera, Special 
allnaion to the tlifterent venous nnnstomoBea belongs to de- 
ecriptive anatomy. Phyeiologieally, the communication lie- 
tween the different veins is such tlnit the blood ean alwaya 
liuJ a way to the heart, and once fairly out of the capillaries, 
it cannot react and influence the circulation of fresh blood in 
tb.e tissuea. 

Collected in this way from all parts of the body, the blood 
JB returned to the right auricle, from the head and upper 
extreoiitiea by the superior vena cava, from the trunk and 



304 



OIBOPLATIOir. 



lower estrcmitiea, Iiy tlie inferior vena cava, and from the 
suTjfitaiiee of the heart, by the coronary vems. 



I 



iSlmciure and Properties of the Vein*. — The structure 
the reina is somewhat more complex and difficult of study than 
that of the arteries. Their walk, which are olwaja muoh 
thinner than the walls of the arteries, may be divided ibtfi^J 
quite a number of lavers ; but for convenience of physiolo^i-^^ 
cal deacription, we Bhflll regard them as prcfceiiting three dts-i 
tinet coata. These have properties which are tolerahlj distino^H 
tive, tbongb not as iimdi so as the three coats of the arteries. 

Tiie iTitermd coat 13 a continuation of the single coat of^^ 
the capillaries and the intecpal coat of the arteries. It ia i^H 
simple, homogeneous membrane, eoniewhat thinnei' than in^^ 
the arteries, lined by a deliuate layer of epithelium. ^j 

The middle coal ia divided by Bome into two layers: am^| 
iiitemal layer, wliitih is composed chiefly of longitudinal 
iibres ; and an external layer, in whicli the fihres have a cir- 
cular direction. These two layers are intimately adherent,, i 
and are quite closely attached to the internal coat. ThaS 
loniritudinal fibres arc composed of the white fibrous tissue^ 
mingled with a large ntiraber of the smallest varjety of the 
elastic fibres, Tlus layer contains a large number of capil- 
lary vessels (im^a vawmm). The circular fibres are com- 
posed of the elastic tissue, some of the same variety a& tbund 
in the longitudinal layer, some of medium size, and i?ome in 
the form of the " fenestrated rnemlirane." In addition, theie 
are white inelastic fibres interhiciog in every direction and 
mingled with capillary blood-vessels, and the unstriped or 
involuntary muscular fibres, whith are always ciroiilar in 
their direction. The muscular fibres are relatively much 
leas nnmerons than in the arterial system. They are most 
abundant in the superficial veins. 

T^hs external eoat is generally composed simply of the 
white fibrouB tissue, like the correeponding coat of the arte- 
rira. In the largest veins, particularly those of the abdominal 




sr^ccrv&T, op tbe vHse. 



305 



aavitr, thiis coat contains a lujer of longituJmal nnstriped 
luurieiilar tibrea> In tlie veina near tlio heart, are i'ontid a tew 
Btriato("Mibro6j which are continued on to the veins Irorn the 
auricles. In eorac of the inferior animals, as the turtle, these 
fibres are quite thick, and jjulsatiuii of the veins in the imm&- 
diate vicinity of the heart is very marked. 

In nearly all veins, the external coat is several timos 
thicker than the iuteriiaL This is, most marked in the larger 
veins, in which the middle coat, partieLdarly the la.yer of 
muscular fibres, is very elightty developed. 

In what are called tha venons Biuuecs, and In the veins 
■which pass through hony tissue, we have only the internal 
coat, to which are superadfied a few longitudinal iibres, the 
whole closely attached to the gniroundlng parts. As exam- 
ples of this, may be mentioned the einuses of the dura mater, 
and the veina of the large bones of the skull. In th« first in- 
E'tance, there is Httle more tlian tlie internal coat of the vein 
firmly attached to the surrounding; layers of the dura niatcr. 
Id the second instance, the Bame thin membrane 3a adherent 
to hony canals formed by a layer of compact tisisue. The 
veina are much more cloaely adherent to the surrounding tia- 
enes than the arteries, particularly when they pass between 
layera of aponeunjsis. This fact has l>oen pointed out hy 
Berard ' as very general, and is one to whieh he attaches 
considerable physiulogieal importance. He cou&iders that 
this arraugement Borves to keep the veina open and give 
tUem additional Btrength. 

The above peculiarities in the anatomy of the veins indi- 
cate considerable dtfferences in their propertteB, as compared 
with the arteries. AVhen a vein is cut acro^, ita waib fall 
together, if not supported by adhesions to surrounding tis- 
anes, so that itj^ caliber is nearly or quite obliterated. The 
yoUow elastic tissue, which gives to the larger arteries their 
great tUickneee, is very scanty iu the veins, and the thin 
walls collapse when not sustaineil by liquid in the interior of 

* Op. fiL, tome iv., p, (P. 



306 



OQCODLAnON. 



tbc vessels. "Wlienpver tlie vciJia remain open after section, 
it is on account of tlieir attaclirnent to siirrouading tis6ues,j 
and is not due to tlie yr&Ui of the vessels tliemselves, * ^ 

Tlioagli with m.ucU ttinner acd appareatly macb weaker 
walls, the veins, a& a nde, ti ill resist a greater preaeure than 
the arteries. Observations on the relative etrengtli of the 
arteries and vt-ins wore made by Hales,' hut the moat ex- 
tended experiments on the subject wltc mnde by CUftoi 
Wiritnnghani, in 1740.' This observer ascertained that thi 
inferior vena cava of a sheep, just above the opening oJ 
the renal veins, was mptnred by a pressure of 176 pounds 
while the aorta at a corres|>onding point yielded to a prossui 
of 1&8 poiuids. The strength of the portal vein was ere 
greater, eupporting a pres^sure of nearly 5 atmospheres, 
ing a relation to the vena cava of 6 to 5 ; yet these vcaaelil 
had hardly one-fifth the thickness of the arteries. In the 
lower estremilies in the biiman subject, the veins are much 
thicker and stronger than in other situations, a provision 
against the increased prensure to whieh they are iMibituallj^B 
subjected in the uprij^ht posture. Wintringham noticed one 
Bingalar exception to the general rule just given. In tlic 
vesaels of the glands, and of the spleen, the strength of 
arteries was much greater than that of the veins. The spleni< 
vein gave way under u pressiire of little more than one atmo»-' 
pbere, while the artery supported a pressure of more than 
Bii atmospheres. 

A little reflection on the influenees to which the venoi 
and arterial circulation are subject will enable us to undei 
stand the physiological importance of iJie great differenL* in 
the strength of the two varieties' of ve^isels. It is true that In 
the arterial system the coustant pressure is greater than in 



eni«H 

no»-™ 
an 

4 



' ^Idticol Esaa^, Tol. li., p. 1Q4 ei leq. Tlicse obserrnUons arit not vnjj sal> 
Li&ctorv. 1b d cziSG where (he *irtMg'l!i nf llie uumtinl and jugular weix" I'oni- 
parvd, in n mare, lltu nir-atJd BUHtaini-d thu gniili^r prc»aiire ; bat it is ituted that 
Ibe jipruUr hnJ been wuikgni-d by repeated rcDCbectioaa. 

* ltiK4itD, op, ed,, tyrwo iv„ |J, i4 tt uq 



PBOPEBTIES OF THE VEINS. 



307 



the vcms; buE it ia nearly tlie Bflme in all tlie ^*;*selB, and 
the iinmeHse extent of the outlet Lnto the cajiiilariea pmvulca 
agaiuat any very great mcirease in pressure, so long as tlio 
blood is in a comiitiun wliidi enables it t-o jms-s into tlie ca- 
pillaries. The uiiiticuhir tibres of tlie k-tl ventricle hnvu but 
a limitwl ]n>wor, mul when the pressure in the arteries h 
such, as it smiietiiriea is in asphj-xia^ us to close the nortiu 
valres 90 tii'toly that the force of t!io ventrielu ^'ill not oiien 
them, it cannot be increased. At the same time it ia b«ng 
graiiually relieved by the capillaries, through wliith the blood 
slowly filters, even when completely unaerated. With the 
veins it i* different. The Uood has a comparatively i-estrict- 
ed outlet at the heart, and is received by the capillaries from 
all parts ol" the STBtem. The vessels are provided with nu- 
merous valves, whieli render a general backward action im- 
possible. Thus^ restricted portions of the venons eyetem, 
from pressure in the vi-sBete, luereaee of floitl from absorption, 
accumulation by force of gravity, and other causes, may be 
subjected to great aud sudden vamtiona in pre^ure. The 
great stren^h of these veaaeU enables them ordinarily to 
fiuflei* these varlfttiona without injury; tlioujih varicose veins 
in various parts jtresent examples of the t-fleets of repeated 
and eoutiuned distention. 

The veius possess a considerable degree of elasticity, 
though this property ia not as marted an it is in the arteries. 
If we include between two ligatures a portion of a vein dis- 
tended with hlooil, and make a sinaU opening in the vessel, 
the blood will be ejected with some force, and the vessel he- 
comes very much rednced in caliber. 

It has been proven by direct e.\periment that the vcidb 
are endowed with that peculiar contractility which is char- 
acteriftie of the action of the nnstriped mupcular fibres. On 
the application of galvanic or uiechaniea! excitation, they 
contract slowly and gradually, the contraction being followed 
by a correspondingly-gnidual relaxation. There is never any 
rhythmical or periptaltie movement in the veins, which is 



90S 



CIECULATION. 



competent to assist the circulation.' The only regalar tr 
meiits wliich oinsuT arc Been in the ves^U in imnitidiate ytox- 
iiuity to tlie right auricle, which arc provided with a few 
fibres eiDiilar to those whii-li exist in ihe waUs of llie beaut. 

Xerves, chiefly trom the sympathetic system, have Ijeen 
demonstrated in the walls of the lar{;er reins, but have not 
been foUoweil out to the smaller ram iticat ions. 

Valves of the Veins. — The diecoverj' of the valvea of iha] 
veins has already been alluded to in counection with the his- 
tory of the discovery of the circnUtion. They bad nndoobi' 
e<ily been observed in various parts of the venous system by 
Cananius, and foand verr generally distribntwl throtighoiat 
this system by Piccolomim, the lost-namied anatomiist haring 
published aa accouat of thera in 13S6; but Fabricius, the 
greatest anatooiist of his day, had the good fortune to detn- , 
onstrate them to his illustrious pupil. William Harveyj^ 
whose itnmorta! discovery inchoated iheir physiological im-^ 
portance. Being ignoraut of the observations of his prwle- 
ce^i^rs on this subject, Fabricius announced him:self ae ibeur 
discoverer, and is generally so regarded. In all parts of the 
venoua srsteoi, except, in general terms, fn the abdominal, 
thoraeic, and cerebral cavities, there erirt little membraDOQS 
semilunar folde, resembling the aortic and pulmonic ralvesof 
the heart. When distended, the convexities of theee Talrebj 
look toward the peripheiy. lu the great majonty of in 
the ratres exht in pairs, but are occaeiouailj &nnd in groapa 
of threa Tliey are formed of the delicate linii^ membraae 
of the veins, with the internal or longitndinal layer of ifae 
middle coat. Some transrase titurs are found anmnd tbo 
baie of the valves, and n few moscular fibres hafe been 

' Tbta l a i f B rt tpffc* paniemhrtyiQ d>c h — loljwL SgUffhwaatfcaA 

rhrthoioal «j«dtM<Hiu or ibc rtim m ihe «r of & nbtil ( L qbb p, T^mim A 

th* n^ |ihiBmiinnw in ^ht vimg oT tlw bu (Toon ud Sow&x nfm'ttwfimt 



yAl,Tj;3 OF TEE VEIKS. 



ao9 



'ftnwed into tlieir folds. Tbore exists, also, a fibrous ring fol- 
lowing tlie liiH3 of attaelimeDL of the valvular curtain* to the 
vein, which renders tlie vessel mueli Btrougor find Ic-ss. dilata- 
We liere thiin in tlic spftces Iwtween the ralve*. The valves 
are by far the most niimeroiw in the vcitis of the lower es- 
Iremities. Tliey are generally situated just bulow tLt! point 
wheivi a sniull vein empties into one of larger siiie, bo that the 
blood, as it pHi^es in, finds, mi immediate oLstncle to pasdage 
in the wrong direction. The fiitnaiion of the valvps may be 
readily observed in any of tlie su^xirlicial veina. If tlie flow 
of blooil be obstrncted, little l\nots will be formeil in the oon- 
gested vesaela, whioh indicate tlie poaitiou and action of the 
valves. The einiple expetiment of Harvey, already referred 
to, preacsnts a striking illiiritralton of tlio atition of the valves, 
"fflien the vein is tlina congested and knotteil^ if tlie linger be 
pressed along the vessel in tltu direction of the blood cnn-eut, ti 
portion silnateci between two valves may be emptied of blood; 
but it is impossible to empty any portion of the vessel by 
pressing the blood in the opjjosite diiection. On slitting 
Opeu a vein, we obsci'vc tbe shape, attachment, and extt-emo 
<ielicacy of strnfaum of the valves. "When the vessel is 
«inpty, or when flnid moves toward tbe heart, they are closely 
applied to the walla; but if liipiid or air be forced in the 
opposite direction, tbi^j project Into its caliber, and by the 
application of their tree edges to each other, eft'ectually pre- 
vent any backward euri-ent. Fabricius noted the following 
peculiarity in the arrangement of tbe valves. When eloeed, 
the application of their free edges tbrms a line whif^h runa 
across the ves^l ; it id fuund that in sneceBfiive Bets of valves 
these lines are at right angles to each other, so that if in one 
Bet, this line has a direction from betbre backward, in the 
Bets above and below the lines run from aide to side. 

There are certain esceptious to the general projiositiou 
tliat the veins of the great cavities arc not pruviik'd with 
valves. Valves are found in the portal syBtom of sonie of 
t!ie infi-rior animals, aa the horse. They do not exist, how- 



810 



CmCULATtOS'. 



evev, in thifl sitimttoti in tlie human aiiUject, Generally, il 
following out ll)c hi-anclies of Uie interior retia cava, nt 
Valves are found imtil vre come to the frural vein ; but ooca- 
EJoiially tbeit! i.a ii ddnble valve at tlju nrij^in tA' ttae txtornii 
ilia<^. In eonie of the hiferinr auiniaEp, tlitre cxif^ts eonstautlj 
a single valvultir fuld in tlio VL-iia cava at the opeiiirig^s iif tin 
hepatic, and one at the ojieniug; of the renal vein. Tfiis is 
not constant in the human subjwt.' Valves are found in tliflj 
spermatic, but not in the ovariau veiua. A single valvuliii 
fold has lieon deiJiTlbed bj Dr. J. II, Bimt«n, at the opcuiD^ 
of the right Spermatic into the vena cuva.' Tliere are two^ 
Talves in the azji^gos vein near its opening into the superior 
vena cava. There is a single valve at the orifioe of tli^f 
coronary vein. There are no valvea at the openini^ of tlie^ 
brachio-cephalic into tlie superior vena cava; but tlieti* is a 
strong double valve at the point where the internal ju^Iar 
opens into the brachlo-ccphalio. Between this point and the 
cnpilbiries of the brain, tlic vessels are entirely deprived of 
valves, except in very rare instances, ■when one or two are 
found in the com-se of the jutrular. 

Ill addition to tlic double, or more rarely triple, vali 
which have JKst been deecribed, there is another raiietjj 
found in certain parts, at the point where a tributary vein'' 
opens into a main trnnV. Tlu3 consists of a single fold wlnyh 
is attached t^o the smaller vessel, hut projects into the larj^J 
Its action 3s to prevent regin'gitation, by the same mechanisii 
as the ileo-ciucal valve prevents the passage of matter fror 
the large into tlte small intestine. Theee valves are mat 
leaa numerous tliau the firat variety. 

' Dr. Crisp, of Erglanil, lin» ii«iTifwiJ nJTtft in (lie Hjilcnio Tcins in eatne of 
the infi'riur animnis. In one of tin* TiriL*eiilt;Tic tii'lfis Of ILl- K-illdecr, liii sbowed 
rorly-two [inira of vakes (-Vfic York Mrliral J^mrmiJ, April, ISfifi, p. fl7)L 

* Dtxeription of a Vaht at the Trmtinnium n/ Ihr UigM Sjirrinitiif Vfiiti 
it> A» Vfrut Cava, miih Rfmarl-n en it* Urltili'mi to VarkoMh. Bj Jogn 3,1 
EMSTOJf, M. D. AmfHiVn Jfvrnal nf tht Mnli^. Seiena*, Julj-. 1850. Tbil 
pn^eiite of this tsItc, according to Dr. Brinion, eiplaiiw tiw moTv (K!{\ica\ i»\ 
carfthco of T*riL'oce-te on tht right side. 



COCfRSK OF tSE BtOoP IN THi; VEWS. 



311 



The veins form a evstem which is athipted to tlie re- 
turu cf Llood to the heart in a coQiparutively slow ami 
unequal current. Distentiim of certain ^rtions is pro- 
vifleJ for; and the vessels arc fit> protected wit!! valves, 
thnt whatever influences the cun-ent mu&t favur ita flow in 
the tliret^tion of the heart. It is a aptem wliick is eal- 
culated to receive the hluod from the parts after it lias 
become nntit for nutrition, and pass it in the reqxii&ite 
riuantitj to the lungs, tlirough the right eide of the heart. 
for regeneration. 



Course of ilm Blood in the Yeins, — The espcnments of 
Hales and Sharpev, showing that defibrinated blood eatj be 
made to pass fmrn the arteries into the cupillnries und out at 
the veiu3 by a pressure less lliau that whicli exiBta in the 
arterial system, and the obHervatlnna of Magendie upon the 
circulation In the leg of a living dog, eliowing that ligation 
of the artery arresti^ the flow in the vein, paints wliicli have 
aU'eady been fully discussed in treating of the causes of the 
capillary cireulationt li^ve eelabljshed, beyond question, t!ie 
iact that the force exerted hy tlie left ventricle ia sufficient to 
account for the venous circulation. Tlie heart muet be cou- 
sidered the prime cause of all niovenicut iu these vessels. 
Rcgartling this as definitely ascertained, there remain to coii' 
flider, in the atudy of the coui-se of the blood in thu: veins, the 
character of the eurrentj the influence of the vessels them- 
selves, and the question of the existence of fyrces which may 
assist the tv!* a tertjo from the heart, aud circumstances which. 
may iiiterl'ere with the flow of blood. 

Ab a rule, in the normal circulation, the ilow of blood in 
the veins ie conlitiuous. The intermittent impulse of the 
heart, which progreBsively dhninishea aa we recede from this 
organ, but is &till felt even in the smallest arteries^ is lost, aa 
we have seen, in the capillaries. Here, for the timt tinjo, the 
blood moves In a constant current ; and as the prossufe in the 
arteries is continually Bupplyiug fresh blood, that which haa 



m 



oatcn.ATiDX. 



('Ir'*t]lul<-i1 in the (-a|iI1larie:6 U forced into the renoos ndjeleft^ 
ill fi t,U-su\y fttrefltii. As tlio ftupplrto tlie capillaries of differ 
tfTit part» U rrgnlnted hy the action of the small arteries, and 
iu) ihl* «iij>l>1.v ii* rtiilfjuft r« frreat variations, Oiere must Deee&- 
•ttril_y Iio coiTiMponding variations Id the iuteasity of tbn^ 
[iurjvnl in tliu voinH, and the qua.Qtity of blood which thc^iaH 
vl'iwcIh rt'wivt'. Aa we fthould anticipate, then, the Tenoiis 
ciiiiululiun i* niibjwit Ui very preat variations arising frf>m ir-^^ 
ragiilarity in the Bnp])ly of hlooj, a^ide from any action of^| 
the vi'HM'lrt (.lii'mnelvos, or any exti>rnHt diaturbinf; influences, 
A jj;nMit vfiriiition in tlio venous current is observed in tbdj 
voirw which collect tlie hlood from the intestinal canii 
During tho intpn'aln of dijjicstion, these vesjwls. carry a cor 
jHimtivcly tiinull qniUitity of blood; but during digestiot 
thcv jiiii Inik'ti with tin* lliiids ret;eived by absorption, and ih 
([iiaiitity IB iiiLnH<iiso]v increased. 

It oWt'ti \ia\}\n'UA that a vein becomes obstructed front' 
aunio cmist' wliich is entirely plivt-iolofric^l, a^ the action of 
luiM-Uv. Tho iinmenso nmnlwrof veins, as compared with 
thy ailories, and their frw". (\>niinunieatioiDs with each oth^a; 
('i>ivi»h' that tlu' i-urrent, tmdi-r Oiw* circumstances, is 
ply ilivrrliHl^ iwisiiitig to tht> heart by another channel. 
BUY iwirt of tliT^ venous ^yftfin is distoadt^, the Tesg*U react 
lut llio UUhhI, and e\t'rt a wrtaiii iuducuce itn the cnrrentf 
alim\-« |vn«ing it towud the heart, for tbc valves oppose the 
flow in the ^ipocilB direeciott. 

Tht* intvnnittwt Mdoa of the tMart, vlueh pemdw Un 
vikolv art^^rial sT«ew» b geBenUr afaaocbed. ba it were, ia 
Uw |iMM^n of tb^bkud tliMa^tfai fTflhriw; iMtvlien 
llwMtM^tMofuy )wn«»nfTHBcki«luad,tWnBpaka 
of tW cvAtnJ orj^an uu^t atend %*> iht vtim. Banard has 
•h»*nitb»iifttW «Mn« «trikM« ■ i Mg, ifc hiiwcfrbMB 
c ifMiwmto en tW cflrMktiM a die ^^atk,^ VWb t^ 



Ctk 



^«*fc. 



COUBSB OF THE BLOOD IN' THE TECNS. 



313 



^rLicli thcj receive is very much increased. It is then fnr- 
m'shed to supply luatenal for the eecretion, and not esclu- 
eively for natrition. If the vein be openeci at sncli a time, it 
ifi found that the blood has not lost iU arterial character, that 
the iiiiiiitity which escaped ia niuth increased, and the flow 
is in ail intemiittent jet, as from a divided artery. This is 
due to the relaxed condition of the arteiloles of the part, and 
the phenomenon t!ma observed ia the true venous pul^, 
What thns Ofcurs in a reatrieted portion of the circiilalorj 
eystem may titke phice in all the tcidb, thougli in n less 
niarkeU di-grce. Ph^siciane have frequently noticed, afli_'r 
the htood has been ilowinj^ for eoiue time, in the operation of 
reneseetion, that tho color changes from hlaek to redj and 
the stream becomes intermittent, often leading the operator 
to fear that he has pricked the artery. In all probability 
the phenomenon la due to the rela^cation of the arterioks, as 
one of the effects of ahstraction of blood, producing the 
6ame conditiou that has been noted in some of the glanda 
fluring their functional activity. The h^'pothesia that it ia 
ilue to an impulse from tlic adjacent artery is not admissible. 
Except in the Teine near the heart, any pnlsalion whieli o&- 
cnrs is to be attributed to the furce of the heart, transmitted 
•with unusual facility throngb tbe ftapillary .system. A nearly 
uniform current, however, ia the nile, and a marked pulsation 
the rare exception. Mr. T. "W. King, in an article on the 
" Safety-Valve of the Iluiiian Heart," ' diseuasing the forces 
which concur to produce the venous circulation, mentions 
the fact that in some individuals, atler a full meal, pulsation 
can be obeerved in the veina of the hand or the median vetna 
of the forehead. Thia phenomenon ia very delicate, and, to 
make it more apparent, he employed a thread of black seal- 
ing was alwut two inches 
rein of the back of the hand irith a little 
make a long and esceeeively light lever, capable of iudicating 
a very blight movement in the vessel. In this way he dem- 



long, which was fixed across the 
tallow, BO as to 



3U 



CEECT L ATltiS. 



onstraled pulsation lu tlie veins of tbe lianrl, aud also i| 
the ann, fnut, ami leg. These iDOvuiuents are verj sUglit 
itn(] are generally only appreciable by some such deltcat 
means of iiirestigatioii. Thia is a stroiig argument in npi>o- 
Bition to the opinion of those tvIio regard the aef ion of the 
lioarE as Inoperative in the veins. In (pertain eases of disease, 
Mr, Iving has noted veiy marked palfladon in the veins of 
the bac-k uf the band, and other vee&els far removed frotaj 
the liearL 



Pressure of Blood in the Yeins.' — The preefture in thi 
veins is always much less than iu the arteries. It is esC' 
ingly variiiLde in Jiflerent pai-ts of the venous system, and iiv 
the same part, at dlHerent times. As a nde, it is in inverse 
ratio to iho arterial pressure, Whatever favore the parage 
of blood from the arteriea into the capillaries has a tenden 
ta diminish the arterial pressure; and, as it incri'uses th' 
qnaiitity of blood Khich paeses iuto the veins, must increa 
the venous pressure. The great capacity of the venous 8 
teni, its numerous anastomoees, the presence of valves whicli 
may shut otf a portion from the rest, are circumsiancea whluh, 
involve great variationB in pressure in different vessels. I' 
lias been ascertained by Volkmann, and this has been con- 
firmed by others, that as a rule tlic pivossure is dimiuibhed as 
we pass from the periphery toward the heart. In an o 
ration on the calf, be found that with a pressure of about 
inches of mercury in tlie camttd, the pres-snre in the met 
tarsal voin waa I'l inch, aud but 0-36 in the ju«;u]ar/ Th 
pressurB is, of course, Bubjcet to certain variations. Muscular 
effort has a marked influence on tlie force of the circuhiiiou 
in certain veins, and, conseq^uently, in these vessels produces 
an elevation in the pressure. As the reduced jiressui-e in the 
veins is due in a measure to the great relative capai-ily of 
the venous system, aud the free communications between the 
vcaaels, it would seem that if it irere posalble to redueo tlii 

' Mujsi-EowjiKDBi, terof «"■ ^ Phytiihfftr, ParU, ISBB, tome ir., p. 839. 



ige 
icjnB 

J 





CAC8EB OF THE VEX0C6 CIKCULATTOS. 



315 



capacity of the veins in a pjsrt, aiul force all the blood to 
■piias t(> the licart h}'' a singlu vessel cori-ea ponding to the ar- 
tery, the pressure in this vcsbcI shouhl he greatly increased, 
PoiseniUe h^is showB this to he the I'aet by the experiinent of 
ligating all the veins coming iVoni a pail, escept one, tvIjioIi 
had the volume of the artery by which the hlt>(.»d was eup- 
pliiid, forcing all the hlood to return hy this &ingle channel. 
This being done, he found the pressuro in tbe vein immensely 
uicreafied, becoming nearly equal to that in the artery.' 

Hapidii/t/ of the Vmon^ Oiretilation. — It is impossihle to 
fix npoa any definite rate aa represent lri« the rapidity of the 
current of blood in the vying. It will be seen that various 
fircnmstances are caprihle of intrea&ing veiy considerably the 
rapidity of the tiow in certain "veins, and that under certain con- 
ditions the current in &onie parts of the venoas eystcra is very 
tnucli retarded. Undonhtedly the generrd innvement of hlood 
in the veina is very much nlower tlian in tbe arteries, from 
the fact that the quantity of Idond is greater. If it be as- 
sumed that tbe cjuantity of blood in the veins 13 doublo that 
coiit;un<-d in the arteries^ tlie general average of the current 
would be diminished one-half. Ae we uear the heart, how- 
ever, tlie flow bccoiijes more uniform, aud progressively in- 
creases in rapidity. 

As the effect of tbe heart's action upon the venouB circu- 
lation is subject to &o many luodifyin^ influences thrungli the 
fliuall arteries and caiiiliarieB, aud as there are other foi-ces 
influencing the euiTcnt, which Bre by no means uniform in 
their action, witli our prcitcut knowledge, eBtimatos of tbe 
general rapidity of the venong cireuhitlon, or tbe variations 
in different vessc-la, would be founded on mere epeculations. 

Caxtses of ifie Yenvus Circulation. 

In the veins, the blood is farthest removed from the influ- 
ence of tlie contractions of the left ventricle; and though 
^ Bebabd, CovTt de Phytiolofftf, Parip, 1856, tome iv., p. 21. 



316 



CTECrLATtOS. 



these arc felt, there are many other causes which combine to 
carry on tfie circulation^ and niany influences by which it is 
retarded or obetrncted. 

The great and uniform force -vFliieh operates .on the circu- 
lation in these vesficH is the vU a tfi^o. We have repeatedlj 
ryJVrred to the entire adequacy of the arterial pr(;>ssiire, prop- 
agated tlirough thecapillaries, to account for the movement of 
blood iu tlie veicp, provided there be no rery great obstacles 
to the current. Tijere are no facts which lead n& to doubt the 
operation of thifi force afi the prime cange of the venona circula- 
tion : and the only (jnestion which artaca is whether there be 
any force exerted in the eapillavies themselves which is snijer- 
arlded to the force of the heart. In discussing the capillary 
cireulatioDf there has been found no direct proof of tho exist- 
ence of a distinct " capillary power" influentinp the move- 
ment of hlood in these vessels ; and consequently all the tn» 
a teryo oiiernting on the circulation io the veins must be 
attributed to the action of the left ventricle. 

The other foreee which concur to produce movement of 
blood in the vei'na are : 

1. Muaeular action, by which many of the veins are at 
times comprcsseil, thug forcing the blood toward the heart, 
regurgitation being prevented by the action of the valves, 

2. A suction force cxei'tcd by tlic action of the thorax in 
respiration; operating^ however, only on the veins in tho 
immediate neighborhood of the chest, 

3. A paH3ible influence in ihe contraction of the coats of 
the vessels themselves. This is marked in the veins near the 
heart, fn some of the inferior anima.l8. 

4. The force of gravity, wlutih operates only on vessels 
which carry blood from above downwai-d to the heart; and 
a little suction force which may 1k3 exerted upon the hlood in 
a small vein as it passes into a larger veBf^et in wUich the 
current is more rapid, 

The obstacles, to the venona circulation are: Pressure 
suflBcient to obliterate the caliber of a vessel, when, from the 




CACSES OF THE TEIfOPS ClllCDI.ATlON 



317 



fi-cc coramuiiicatiori "with othor vt^eels, the current is simply 
<]iverted into another channel ; the expulsive cfiorta of res- 
piration ; the eoiitrnctioiiB of the right siile of the heart ; and 
tliG force of gravity, nhic-li operateii, iti the erect posture, oo 
the current m all ext'eiiting the veins of the head, neck, and 
pai-t& of the Iriiuk above the heart. 

Tnjiu-f'iice of Muaculur Citnirariion. — That the action of 
inuBcles Laa a considtTaltle influence on the current of blood 
in the vcing situated hetwceu thorn and in their Biibstance, hag 
long been rec^guiKcd It is cxeinplitied in the operation of 
venesection, when it is well known that the jet from the vein 
fany ho Terj much increased in furce "by contraction of the 
inuacles betow the opening. This action is so marked, that 
tlie [utirtri of the venous system which ure sitiiatec] in the Bub- 
etanue of mnseles have been eompured by Chaasaignac to a 
e^Hinge full of liijuid, vigorously pressed by the hand.' It 
inuBt always be roiueiuhcrud, huwever, that thongli the 
musded are capable of acting on the htood L'ontaine<l in veins 
in fh<-ir substance with ^reat ^-igor, the heart is fnlty capable 
of producing the renous circulation withont their aid;, a faut 
whidi is esonJi>lified in ft Btriking manner in the venotis cir- 
culation in paralyzed parts. 

It haa been shown by aetual observations with the hrenii- 
dynanitiraeter, that muscular action is capable of immengely 
increasing the prestnure in certain veins. Tlio flret definite 
experiments on this subject were made by Magendie, who 
showed a pressure of over two inches of mercury produced 
by a general niuseular contraction, on tlie passage of a gal- 
vauic curreut from ,ii iiecdlo plunged into tlie cervical region 
of tlie spinaL marrow to one lixed in the mueclee of tlie thigh.* 
The C'Speriineuts of Bernard have i^hown this more accurately, 
Thia pliyfilologist found tlfftt the pressiu-e in the jugular of a 
horse, in repaie, was 1"4 inch ; but the action of the muscles in 

' BiBASn, op. eit., tome it., p. G7. 

' Mjoentie, Phin^minti Pfi^fti^u^ Alia Vif, Parlft, 184S, Unae UL, p. 163^, 

Si 



819 



CinCULATION. 



raisino^ ihe head iiicreiised it to a little more than five inohc 
or nearly four tiniee.' These observfltions show at once th< 
gteAt TArifltion^ in the veuona cnrrcDt, and the iaiportanl 
influence of musculftr cotitraction on the circulfltioti. 

In order tliat contractions of inneclea shall asBiBt ths^_ 
venouB circulation, two things are necessary : ^M 

1. The contraction niuBt be iuterniittent. This is nl\rnyB 
the case in the voluntary mnaclea. It i& a view entertained 
by many that each muficular fibre relaxes iiii mediately alVer 
its contraction, -Brhich is instflntaneous, and thiit a certain 
period of repose is necessary before Jt can contract again.^ 
However thla may Ije, it ia well knowm that all active ninfrW 
enlar contraction, as distiagiiiehed from the eftorts necessary 

to maintain the hoUy in certain oi-dinary pcwitions, i& inters 
oiitteut, ami not very pi"olonged. Thus the veins, which are 
partly emptied by the conipreBflion, are filled again during 
the repose of the muscle. 

2. There should be no possibility of a retro^ade mov< 
ment of the blood. This condition is fulfilled by tto adioi 
of the T;ilveB. Anatomical rcscarcheg have shown that tht 
valves are most abundant in wins situated in the sabfitanc 
of or between the musclc6j and that they do not exist in the 
veins of the cavities, which are not subject to the s.ame kind 
of compression. It is tliuB that the blood is prevented from 
passing backward toward the capillary system ; and wha^B 
the caliber of a vein i& reduced by eompreesiun, part of Ita 
contents must be forced toward the heart. This action of 
the valves conBtitotes their most important function, 

Milnc'Edwards alludes to an important phyBiologicafl 
hearing of the acceleration of the venous cireuhition Tiy con-f 
tractions of muscles, on their nutrition." It ie appatentlyl 
neces&iiry that the supply of blood should he iiiicrettsed in a 
muscle) in proportion to and during its activity; for at that. 

' Berhabk, Lefont jur ia Phi/inelojyif rf ta PathtJaffil ift Syitemt .Vefcrtte.^ 
PBri», I8f.8, tome i., p. 285. 

' Ltpm* *ur la Phj/tiolagif, UkuC is., p. 310. 



CA.C8Efl OF THE TEMOnS CmOULATlOH". 



ai9 



time the activity of clUassimilntion is undoubtedly augmented, 
ODd there \s an increased demand on the blood to supply tho 
waste. It is apparently a provision of Nature that the ac- 
tivity of a miiflch', fiic'i I Stating the passage of Wood in its 
veinsj and consequently ita flow from the capillarie&, induces 
an increased supply of the nutrient fluid. A& tho develop- 
ment of tissues is generally in proportion to their vaseularity, 
this may account for tlie increase in tho development of 
muscles, wliieli is the invariable result of continued esereifle. 



Force of Aspiration from the TJiorax. — During the act 
of iuspiiation, tlie enlargement of the thorax, liy depresiion 
of the diaplira^i and elevation of tlio ribs, affects the move- 
menti? of fluids in all the tubes in its vicinity. T!ie air rusbea 
in by the trachea and expands tlie Inn^a, so that they follow 
the movements of the thoracic walls. The flow of blood into 
tho great arteries is somewhat retarded, as is indicated hy 
the diminution in the arterial preestire ; and fiually, the blood 
m the great veins passes to the heart with greater facility, 
and in increased quantity. This last-mentioned phenomenon 
can be easily observed, when the veinfi ai-e prominent, in pro- 
found or violent inspiration. The veins at the lower part of 
the neck are then seen to empty tbemBelves of blood during 
the inspiration, and become distended during expiratlotij 
producing a sort of pulsation which i$ synchronous with res- 
piration. Tlaid ('ao always be observed after expo&ure of tho 
jugular in the lower part of the neek in an inferior animal. 
Alter this operation^ if we cause the animal to make violent 
respiratory etJbits, t!ie vein will be almost emptied and eol- 
hipaed with inspiration, and turgid with expiration. The 
movements of the veins near the thorax have long been ub- 
Berved and deseribeii with tolerable aeeuracy. By the fol- 
lowing simple yet conclusive experiment, the regular action 
of the suction force was demonstrated by Magendie. Having 
introduced a gum-elastic sound into the jugular vein of a dog, 
and passed it dowu to the right am-iclc, he eaw '' that the 



320 



CtRCCLAnoN. 



liluod flowed from tLe extremity of the Found only in the 
moment uf espiratioD, We obtain rcBults entirely analogous 
if we introduce tbe sound into the cniral vein, directing it 
toward the abdomen." ' Aa several contractions of the right 
ftnriolo occur between two acta of r0s[3ira(Ion, it is sltown by 
this esperimeiit that, during inspiration, the suction force is 
sufficient to co^interbalanee the contractions of the auricle^ 
which would otherwise f^^i-ce a certain quantity of blood 
thnmjrli tlie Eonnd, a?? it does duricg expiration ; ibr then we 
have a jet synchronous with tbo beats of the hcort. Cathe- 
terization of theri;^'ht eldeof the lieiirt is now (juite a roimnon 
experimeut ; and we have frequently observed the vjiriationa 
in tlie flow of blood from a Bound introduced tlirouf^h the 
jugulap, ^vhiuh wero laicntioned by Magendie, Tbe suction 
force is Btill more strikingly eslubited in tliis operation by 
the entrance of air, which ifi frequently drawn into tbe heart 
during a vli'lent inspiration. 

The influence of aspiration ou the circulation in the veins 
was still more minutely studied in 1825 by Barry, whoee 
moat important experiiiienta have been repeated, %vith some 
luodilications, by I'oiseuille. Barry inti"odnced through the 
jugidar of a horse a bent tube of gla&a, one extremity being 
passed into the right cavities of the heai-t^ or (he vena cava, 
and the other into a vespel containing a colored liquid. He 
fonnd that with each act of inspiration the liquid mounted 
up in the tube, demun&tratiug tbe operation of a notable aue- 
t.i<jn force, Tbe observations and expeiliiienla of Barrj' wcro 
made on. quite an extended scale, but manyof hia condusiona 
were not entirely warranted. He studied, for example^ The 
effect of preventing the entrance of air into tbo elicat by tbe 
trachea, and found that thi* increaeed tbe suction force very 
considerably, as indicated by tbe greater elevation of liquid 
in the tube with each inspiratory effort; but be supposed 



' Maoesdik, Irijunnr* Jti MvUi'trurtiU tie itt P&itriiie el rtut EfoHl «ur Ai ftV 
mlaiioH Ju ^tiff — Journut ik Ph^ologit Kcperiiiunlidf, Viios, 1^21, tuint! i,, 
p. 186. 



CArSES OF THE TEHODS CIROirLAtI<Hr. 



321 



^E bee 



nt this force from tlie tltonix waa felt in the entire venous 
'Stem, tin opinion whicli, aa we shall see, the most simple 
ohservatioiia have shown to he entirely erroneous.' Afl this 
is not felt thtoughoot the whole of the venous systeni, 
E beconiea a queetion of interest to determine ho'w fiir its in^ 
I fliieni;e exterui», and why it 13 restricted to certain vessela. 
Like tlie action of the mnsL^nlnr Byetem on certain veins, It is 
ainiply superadded to the furfic of tlio heart, the latter being 
I entirety eonipetent to keep up t!ie venous c-ircnlation. A 
I proof that it ia not essential is seen in the fact that tlie circu- 
lation is efFected in animals wliicli Jo not inspire, bnt Rwallow 
their air,' and in the foBtus, belbre any movements uf respi- 
I ration take xdace. 

^K Direct observations on the jugulars ebow eonflusivcly that 
^^je inflafnceofinspirati^in cannot he felt much beyond these 
vesselfl. They are seen to collapae with each inspiratory act, 
a, condition whidt liiuiifi thi& influence lo the veins near the 
henrt. The flaccidity of the wallsof the veine will not permit 
the extended actiouof any snction fiiree. If a jmrtion of a veiii 
removed from the body he attached to the nozzle of a, syringe, 
imd we attempt to draw a liquid through it, thoTiffh the snc- 
tinn torce l>e applied very gently, Trhen the vessel has any 
considerable length, its walls vrill be drawn (-ngether. In the 
cireulutiuii, the veins ai'e moderately di&tended with blood by 
the v^is a U'ryo^ and, to a certain extent, supported by con- 
nections with BiiiTuundinf; ti^uesj so that the force of aspira- 
tion is felt farther tjjan in any experiment on vessela re- 
moved from the iMwiy, The bluod, as it iipproaehea the 
thorax, impelled by other forces, it, conaiderably accelerated 
in ild How ; but it is seen by direct oljseiTationj that beyond 

' BjtftFtr. Rfcfu-rc-fiti KrprriniDiitalea nur Ira Carua <iit Ifauvemmi du Sanff d^fti 
(m \''-iiice, Turis, 1S25, p. 12 tl Mf/. 

* la tnnay uiiiLii.ilB tliiit hikv tliu uir iiiFo lUv tunga by an net like tlint mf i]^ 
glulilion, iJiiTt -nre rtgiilur pnlnniiims in llm Tijiiis near tlie livo-rt, nliiuh uri; quite 
nbunilanUv provkleJ wiilnnii^ciiliiT fibres Vikn ihoFU Toumi m tin- lienn. It is % 
qiioation Kbcthcr this dues noi rnke tlie ptaca of the Huvtion foccc Ibam (he eiieet, 
whidi aEH»«tes in other uumnls. 




322 



CIBCULATIOIT. 



a portain point, find tliat very near the chest, ordinary aspi 
ration has no influence, and Tioleut efi^i>rt5 rather retard than 
favor the ctjiTeiit. 

Id the liver, the influence of inspiration becomes a verj 
impurtaut element in tlie produetidn of the circiilatioti. 
This organ presents a vascular arran^enit-nt wbieb is excop- 
tionaL The blood, distribnted by the arteries in a capillary 
plcnis in the mnoous membrane of the alimentary canal and 
in the Bpleen, itistead of Ijeing returned direotly to the heart 
by the veins, is eolleeted into the portal vein, carried to the 
liver, and there distributed in a etcoud set of capillary vesiseK 
It is tlien colleeted in the hepatic veiusj anil (.'aiTjed by the 
Tena cava to the heart. This double capillary plexus be- 
tween the left and right Bidea of the lieart Las been cited as 
au argument agaiii&t the fiu:t that the left ventricle is capable 
of Bending the blood tlirough the entire circuit of the va&ca- 
lar system. The three hoptitic veins open into the inferior 
vena cava near the point where it jiaases the diaphragm, 
■where the force of aspiration from the thorax would mate- 
rially assist tike current of Wood. On following these vessels 
into the eubstatice of the liver, it h found that their walk are 
BO tirnily adherent to the tissue of the organ, that, when cut 
acroeis, they remain patulous; and it ia evident that they re- 
main open under all conditions. The thorax cao therefore 
exert a powerful influence ufjon the hepatic circulation; 
for it ia only the flacchiity of the walls of the vessels whieh 
prevents this influence ft'om operating throughout tJie entim 
venous syetem. 

Though this tuost be a very important element in tli© 
production of the circulation in tho li'^'er, the fact that the 
blood circulates in this organ in the ftetus l>efore any luove- 
meuta of the thorax take place shows that it Is not absulutfr 
ly eaaential. All of the influences which we have tlrns far 
considered are merely suppiemenEary to the action of the 
great central organ of the circulation. 

A farther proof, if any were needed, of the suction farce 




THB 



393 



of isBpiration is found in an acddent wbicli is not iufrequent 
ill surgical operations in the lower part of tlio neck. When 
the veins in this situation are kept open by a tumor, or by 
induration of the Eurroumllng tissnea, an inspiratory effort 
has ofCasionftlly been followed by the entrance of air into the 
circulati'.'n ; aa accident which is liable to lead to the gi-avest 
results. This occurs ouly when a divided vein is kept patu- 
lous ; and the accident proves both the influence of inspira- 
tion oil liquids in the veins near the chest, and its restrielion 
to the vessels in this particular eiUiation by the flaccidity of 
their w:il!s. The eonditions under which this occurs may be 
imitated in the lower animals by introducing a tube through 
the vein into the thorax; when, with a riolent act of inspi- 
ration, air will be drawn in^ iind the curious and startling 
eli'ects upon the circnlation nmy be observed. 

A full discussion of the subject of air in the veina, 'wHch 
is of great pathological interest, does not belong to the dorauin 
of jiliysiology. The blood is capable of dissolviug a certain 
quantity of atinoRpheric air; and a Biuall quantity, very grad- 
ually introduced into a vein, can be disposed of in this way. 
When, however, a conBiderahlo quantity suddenly linde its 
wiiy into the venous system, the patient, or animal, experi- 
ences a sense of mortal diatresa, and ahnost immediately falls 
iuto R state of iueensibility. A peculiar whistling sound ie 
heard wh<.'ii the air puasfs in ^ and if the ear be applied to the 
cliest, we distinguish tlie hibored eflbrts of the heart, accom- 
panied by a loud cliumiug eound. On opening the cheat 
after dL'ath, the right eavitieu of the heart are invariably 
found distended with idr and blood ; the blood being frothy 
and florid. Generally the left side of the heai't is nearly or 
quite empty. 

The production of droth from air in the veiiia la purely 
mediaulcid. The air, tinding its way lo the rip;ht ventricle, 
is mixed with the blood in the form of minute btihblea, aud 
passed into the pulmonary artery. Once in this vessel, it ie 
impossible for it to pass through the capillaries of the lungs, 



CIKCrLATIOy. 



and death by euffoention ie tlie inevitaljle rrault, if the qniin- 
tiiy of air bo largt'. It is because no blood can pasa tlirougb^ 
tlie Iiiiigd, tliat the lisfl cavitiefi of the heart are usually fuiitid^| 
empty. 

Certflin caaca of entrance of air into the Teins in surtjiea^— 
opemtioDg, thongh pieseuiing the niost {Ltatniiuf; iuiuiedfat^J 
B_)'inptoui6, have tonuinoted in recovery. lu tbeae instances, 
the qnantity of air is not sufficient to cornpletely bWfc up 
the pulmonary capillaries, and it ia gradually absorbed by 
the blood. fl 

Air injected into the arteries prodnees no such serious ef- 
fects aa air iu the veins. It is arrested in tie capiUarieti of 
certain parts, and in the course of time is abaorbed wilhoi 
bavhtg proditt^ed any injury. 

Aside from the ]ires*iue exerted by the contraction 
muscles^ and the force of aspiration from the thorax, tlie ii 
JIueiicefl which assist tho venous circulation are very elight 
Aa far as the action of the coats of the vessels themselves ts 
concerned, their contractiou, it must be reineoibered, is slow 
and gradual, like the contractiuu of the arteries; and it 
hardly possible that in the general venous «j^tetn it ebouk 
operate at all on the blood-current, bej'ond the simple infln- 
ence of the rednction of the caliber of the vesseL There 19 
H sliglit contraction in the veiue cavte, in the inime4.1iate 
jiruximity of the heart, wdiieh is very much more e::teuded 
ill many of the lower vertebrate animals, and may be nien- 
tioued OA having an induence, very in^igniticont it is truo^^ 
on the iloiv of blood from the great veins. If 

In the veins which pass from above downtt"ard, the f.irue 
of gravity favors ihe flow of blood. This \& seen by the tur- 
geecence of the veins of the neck and face^ vrheQ the bead is 
kept for a short time below the level c»f the heart. If the 
ami be elevated alcove the head, the veins of the back uf the 
band will bo mudi reduced in size, from tlie greater facility 
with which the blood passes to the heart ; vhile they an 



rDHOTTOH' OF THK TALVB. 



325 



iliKteniled when the hand 19 uUowed to hang by the side, and 
the blood lias to mount up against tlie force of gravity. 

In the extreme irregularity in the rajiidiiy of the circula- 
tion in different veins, it must freqnentlj happen that a ves- 
eel e4ii|ities its blood into another of larger size, in which the 
cuiTent i£ more rapid. In siu'h an instance^ aa a physieal 
ncceHaitv, the more rapid currcut ia the larger vessel exerts 
a eertjiiu 6uction force ou the fluid iu the vessel wliich 
joinfl with it. 

Funotioa of the Valves. 

With our present knowledge, it ia difficult to eompre- 
hend how any wmituutlst could have ateurately described 
llie valves of the vein*, and yet be ignorant of then- function; 
and the fact that their use was not uiideratood before the 
description of the circiulation bj Harvey, shows the greatness 
of this us a di&covery, aud the shallow eharauter of any pre- 
tence that men of suieueo had any idea of the motion of the 
Ijlood bcforu his time. 

With our present knowledge of tlie conrae of the blood, 
it is evident that the great function of the valves ia in pre- 
fienting an obstficSe to the reflux of Wood toward the capil- 
liiry system; aud it only remains to study the canditiuns 
under wliich they are brought into action. 

Tliere are two distinct conditions under whii;h the valves 
of the veins may be closed. One of them is the arrest of cir- 
culat,iH)n, from any cause, in veins in which the blood hna to 
iiiouut against the force of gravity ; and the other, compres- 
eion of veiii6^ from any ennse (generally from muscular eon- 
trat'tion) wiiich tends to force the blood from tha vessels 
compredseil into others, when the valves offer an ob^trnction 
to a flow toward the eapillariea, and neceasitate a current in 
the direction of tlie heart, 

la the first of these eouditiuua, the valvea are antagonistic 
I to the foi-ce of gravity, and, when the caliber of any veaael ia 



326 OIBCaLATION. 

temporarily obliterated, aid in directing the current into an 
astomutic vessels. It is but rarely, however, that they act 
tbna in opposition to the force of gravity ; and it 18 only 
when many of the veins of a part are simultaneously com- 
pressed that they aid in diverting the current. AVlien a sin- 
gle vein IB obstructed, it is not probable that the valves are 
necessary to divert the current into other vessels, for this 
would take place in obedience to the vig a tergo ; but when 
many veins are obstructed in a dependent part, and the 
avenues to the heart become insufficient, the numerous 
valves divide the colamns of blood, so that the pressure is 
equally distributed through the extent of the vessels. For it 
must be remembered, the strength of the walls diminishes as 
we pass from the larger veins to the periphery^ and the small- 
est vessels, which, were it not for the valvoa, would be sub- 
jected to the greatest amount of pressure, ara least calculated 
to bear distention. This is but an occasional function which 
the valves are called upon to perform ; and it is evident that 
their influence is only to prevent the weight of the entire 
column of blood, in vessels thus obstructed, from operating 
on the smallest veins and the capillaries. It cannot make 
the labor of the heart, when the blood is again put in mo- 
tion, any less than if the column were undivided, as this 
organ must have sufficient power to open successively each 
set of valves, when, of course, they cease to have any influ- 
ence whatsoever. 

It is in connection with the intermittent compression of 
the veins that the valves have their principal and almrat-con- 
stant function. Their situation alone would lead to this sup- 
position. They are found in greatest numbers throughout 
the muscular system, having been demonstrated by Sappey 
in the smallest venules. They are also found in the upper 
pai-ts of the body, where they certainly do not operate against 
the force of gravity, while they do not exist in the cavities, 
wliere the venous trunks are not subject to compression. It 
has already been made sufficiently evident that the action of 



rALVEfl. 



xonadfiB Beconda most puwerfullj' the contractions of tJie 
tenrt. The rr* a ter^o from the heart is, donhtlosF, generally 
sufficient to turn this inflnence of muscular comprePBion from 
tLe eapillaiy system, and the valvea of the veins are open ; 
but they stand ready, nevartheleaa, to nppoao miy tendency 
to regurgitation. 

In the action of innaeles, the skin is frequently eti-etched 
dver tlie part, and tlie cutaneous veins arc- Bornewhat com- 
pressed. This may be seen in the band, l)y letting it hang 
by the side until tbo veins become somewhat swollen, and 
then contracting the miisclea, when thu skin will become 
tenae and the veiaa very much less prominent- Here the 
valvea have an important action. The compresBion 'of the 
veim* IB much greater in the eubetanee of and between the 
musdeethati in the skin; but the blood is (breed from the 
museles into the skin, and the valves act to prevent it from 
taking a retryj^rade course, The fact that the conlraction uf 
mnBcles forces blood into the veins of the skin nmy be seen 
by Burraiinding the ii]iper part of the forearm with a moder- 
ately tight ligatiii-e, wliich will distend the cutaneous veins 
below. If we now contract the muscles vlgoronsly, the veins 
below will become sensibly more distended and knotted; 
ghowiug;, at once, the pas&uge of blood into the skin, and the 
action uf the valves. 

When a vein is distended, by the injection of air or a 
liqnid Ibreud against the valvea, it is obBerved that at the 
point where the convex borders of the valvre are attached, 
the vefflel is not dilated as much as at other pans. Thi^ ia 
due to the fai^t that the valvea are bordered with a fibrous 
ring, which strengthens the vessel, and prevents distention at 
that point, which would separate the fi-ee borders of the valves 
and render them insnffieient. 

A fuK consideration of the venous ana»*tomoses belongs to 
deBcriptive anatomy. SulKco it to say, in this connection, that 
they are very numerous^ and provide for a return of the blood 
to the heart by a nomber of channels. The azygtB vein, the 




33S 



CmOCLiTTON 



veins of tlie ppinal canal, and veins in the walls tf tlie ab<l«> 
men and thorftx, conneRt the inferior vritli tlie superior veiia 
cava. Even the portal veia hns latelj been shown to Imve 
its communicntiona witti tUe general venons sjst^m. TlinSj 
in aU parts of the organism^ temporary compression of a vein 
OTiIf diverts the current into some other vessel, and permanent 
obliteration of a vein produee* eulargeuient of commanicating 
bfflnches, "which soon becoinesufticieiit tameetall the rotiuir©- 
raeuts of the circulation. 



Conditions which imjpede t/ie Yenous Circulatiort. 

Trfflutince of Expiration. — The in^uence of expiration on 
tbe circulation in the veins near the thonix ib directly oppo- 
site to that of inspiration. As the act of inspiration hoa a 
tendency to draw the blood from these vessels into the cheat, 
the act of exj-iration has a tendency to force tbe blood out 
from tlie veasela of the thoras, as the air is forced out by the 
trachea, and opposes a flow in tbe opposite direction. Tbe 
effect of prolonged and violcat expiratory efforts is very 
marked ; being followed by deep congestion of tbe veins of 
tbe face and neck, and a senee of fulneaa in the head, Trhidi 
may become very distressing. The opposition to the venous 
eun-eut generally extends only to vessels in tbe iiuniediato 
■\ iulnity of the thorax, or, it may be stated in general terms, 
to those veins In which the flow of blood is assisted by tbe 
inoveuientsof iiispiraticm ; hut, while the inspiratory infliieneo 
is itbsotutcly coutined to a very restricted circnit of veaiiGls, 
the obstructive influence of very violpnt :vud prolonged exi)i- 
ration may be extended very uiucb farther, as is seen when 
tile vessels of tbe neuk, laccj and conjunctiva become con- 
gested in prolong^ vocal efforts, blowing, etc. 

The mechanism of this is not what we mig'ht at fiist be 
led to snppoHo ; namely, a mere jvllux from the large trunks 
of the thoracic cavity. Were tliis the case, it would be ne- 
aessary to assume an inaaffiuiency of certain valves, whicb 



SEGPRGITAHT VENOUS PULfiE. 



339 



doe^ not exist. In estreme congestion, reflux of Wood mftjf 
take place to a certain exteut in the esterual jugularj fur this 
vessel haa bnt two valvc-Sj whidi are not competent to pre- 
vent re^irgitatioti : ' but tbe chief cause ct' cotigoetion !« 
due, not to regurgitation, but to accumulation from the pe- 
ripheiy, and an obbtructimi to tiieflowof bloud into tbo great 
resseJs. 

It is in the internal jugiiiiir that the influence of ejspiration 
is must important, both from thej^'i-eat size of the vessel in the 
bnman Bubject, ai compared with the other vessels, and trom 
the iraportfince and delitaty of tlie porta frum which it coltecta 
the blood. At the openinc; of this vessel into the innominate 
vein, ia a pair of strong and perfect valves, -wlueh effeeluallj' 
■close the urilii-e when there is a tendency to regurgitation. 
These valves have attracted much attention among pbvsiolo- 
giats, since tbe discovery of the circulation has made it eri- 
dent liovr important they might be in protecting the brain 
from refliLx of blood. When the act of expiratiuu arrests tlie 
onward flow iu the veins near the thorax, these valves are 
closed, and effcctnally protect the brain from congestion by 
regnrgitation. The blood aceanmlateB behind the vatvea, but 
tlie free comiiianlcation of tbe interna! jugular with the 
other veins of the neck relieves the braiu fi-om congestion, 
unless the eflbrt be extraordinarily violent and prolonged, 

The above remarks with regard to the infliicmie of exjiira- 
tion are applicable to voeal efforts, violent coughing ortiueoz- 
ing, or any -violent muscular efibrts, eueh as strainlngj in 
■which the f;lotti9 is closed. 

SegurgitatU Yenmi^ Ptdse, — In the inferior aniraala, like 
the dog, if the external jugular be exposed, a distention of 
the vessel is seen to accompany each expiratory act. Thia is 
sometimes observed in the human subject, when rcBpiration 
is exaggerated, and haa been called improperly the vonouft 
pulse. There ia no sufficient obstacle to the regurgitation of 

' Gii*T, DmeripUvt Analomtf, Philadelpbia, IBM), p. 404. 



330 



C3IBCULAT10N. 



blond from the thorni into the external jiignkr, and distiiiPt 
pulsations, syiichmnou,^ wiili the movements of respiration. 
may lie produced in this way. 

In some forttts of cardiac disease effecting tlie riffht eido, 
a pulsation, BjTiuliroiious witli the heart's action, has also 
been noticed. This ia always coniiued to the jngnlar, and 
miiat not be connected with tho aUg;ht pul&ations which 
Bometimes. occur in the veins of the extremlUea, It 16 due to 
a regurgitant impulse from the right side of the heart; and 
genL-rally, to the fiction of the right ventricle, propagated into 
the veins on account of pathological insufficiency of the tri- 
cuspid valves. Two distinct pulRations npcompanying each 
act of the heart have been occaaionally observed , one im- 
mediately preceding, and the other coititiding with, the ven- 
tricular eyatole. In a case of thie kind, poet-nuirtem examin- 
ation revealed contraction of the right an rienlo- ventricular 
orifice, as well as insufficiency of the tricuspid valves." The 
relation of the pnl&ation of the Jugular to the action of the 
heart showed that the iirst impulse was produced by the con- 
traction of the right auricle, and the second by the coatrac- 
tion of the right ventricle. 

It ia evident that there are various ether circumBtances 
which may impede the veuoue cii'culation. Accidental 
compression iniiy temporarily arrest tho flow in any par- 
ticular vein^ WicE the whole volume of blood is materi- 
ally increased, ha alter a full meal, witli eopiouB ingestion of 
liquids, the additional quantity of blood accumulates chiefly 
in the venous system, and proportionately dimiuiaitea the ra- 
pidity of the venous cireulaiion. 

The force of gravity also has an important influence. It 
h much more di^cnlt for the blood to mount from below up 
to the heart, t!ian to flow downwardg from the head and 
neck. The action of this ig seen if comparison be made be- 
tween the circulation ia tho arm elevated above the head 
and hanging by the side, In the one case the veins are read- 

• Finrr, BUeata of l/se Start, PhiUdelpSiia, IBBIP^ p. 147. 



EEOUEGITANT VKS0U8 PCLSE. 381 

Ily emptied, and contain but little blood ; and in tbe other 
the circalatioQ is more difSctdt, and tbe vessels are modei-ate- 
\j distended. The walla of tbe veins are tbieke:*t, and tbe 
Talvea most numerous, in parte of tbe body wbiuli are babit- 
ually (tependent. Tbe influence of gravity is exempUtied in 
the prodnctioQ of varicose veins in tbe lower extremities. 
This disease is frequently induced by occupations which re- 
qaira constant standing; but tbe exercise of walking, aiding 
tiie venous circulation, m it doee, by tbe muscular etfort, bag 
DO such tendency. 



CHAPTER JX. 

PECULIABITIES OF THE CIECULATION IN DIFFKEENT PABT8 OF 
THE BT6TEU. 

Circulation in the cranial cavity — Circulation in erectile tUsuea — Derivative cutn- 
lation — Pulraouarj circulation-— General rapidity of the circulation — Time re- 
quired for the passage through the heart of all the blood in the organism — 
Relations of the general rapidity of the circulation to the frequoicy of the 
heart's action — Fheoomena in the circulatory system after death. 

Circulation, in the Cranial Cavity. — In tlie encej^lialic 
cavity, there are certain peculiarities in the anatomy of some 
of tbe vessels, with exceptional conditions of the blood, as re- 
gards atmospheric pressure, which have been considered ca- 
pable of essentially modifying the circulation. In the adult, 
the cranium is a closed, air-tight box, containing tbe incom- 
pressible cerebral substance, and blood ; conditions ■which are 
widely different from those presented in other parts of the 
system. On this account, some have gone so far aa to con- 
sider any change in the quantity of circulating fluid in the 
brain, a physical impossibility.' Pathological facts in oppo- 

' A number of years ago, there was considerable interest excited in the di^ 
cushion of (he possibility of an increase or diminution in the quantity of blood in 
the brain under any circumstances. Monro, Abercromhie, and Dr. Kellie sup- 
posed the quantity of blood in the brain to be invariable; Dr. Kellie assuming to 
have proved this position by ciperimcuts which showed (according to his conclo- 
flionfi at least) no diminution in the quantity of blood in the brain in aninuls 
killed by Jicmorrha^e, and no increase in the quantity in animals killed by a lig» 
ture around the nock. Uc made other observationa on this subject winch it ia un- 



ciuCplation in the ceakitjm. 



sas 



«ition to such a view are so iiuineroua and wcil cstablislieii, 
that the qufsition does not demjuid extended discussion. It 
b well kuown, that in tertaiti cases tlie vegeek of the bi-ain 
aod its membranes aro found engorged with blood, and in 
others containiug a comparatively amall quantity ; but it ia 
fjievertbelesa true that there are anatomical jwoiiliaritiee in 
these parts, the efiects of which on the circulation present 
important and intercating points for study. 

In the brain^ the venoua pawifLgea which correspond to the 
great veins of other parts, arc sinuseB between the folds of 
the dura mater, and are hut slightly dilatable. In tlie per- 
f$ctly-cou.^ylid;itod adult bead, the blood is not subjected to 
atmospheric pi'essnrc a& in other parts, and the semisolidB 
and liqit Ida which compose the erifcphalic masB cannot in- 
crease in size in conge.4ionv and diminish in ann?rnia. Not- 
withelaiiding these CLUiditionB, the undoubted fact remains 
that examinations of tbe ves^-^els of the brain after dcEitli bIiuw 
great differences in the quantity of blood which they contain. 
The qnestion, then arises aa to wliat is displaced to make 
room for tbe blood in congestion, and what supplies the 
place of the blood in ani^raia. 

An anatonueal peculiaritj'j which has not yet been eon- 
iidered, offei-s an explanation of these phenomena. IMagen- 
die has ehown by observations on living' animals, conJirnied 
by disBCctions of the human body, that between tbe pia mater 
ftnd the araeiinoid of the brain and Bpinal cord there exists a 



ILEoeuar7 to ennmerale. Tteae c*ptrimenl9 wpro fully retiewed bj Dr. Gvorge 
BurfowB, wlio sliows h> Ilia (inotatioDrt from Dr. Kfllie thnt lliey proved notUng 
of (he kittii- Or, B, ri'p<?a1eiJ the oiiwrimputs on tnbbits, tini dcrnonstralfd thut 
(TOttl reriniiflHH esist io llie qnniitiey of blood in llie brftin, wbon llic nnimula are 
killeii ID differmt waye. Ho .^htiweJ itiat tbe bloHKl-rfaaels ate engorged when Ibo 
bead ]» Ifft depwiileoi fur ik number of hoiira, oniJ tbat tlw-y i^ontnm but litilo 
blood when il b ckvatc-Hi. Ci^rtain «f KL-lUg-'a cil^nioBnts, died bj Dr. DiUTOwa, 
8L»w ilml tJie difftretice is ID Hie coULluBiona. nnil BOt 3n the oiperimmtal 
tulB. For u full diifuasioti of 1I1I3 Bubjcct, tlid reatlut U reremsl I0 the work 
of Dr, Biimjws «q Diofnltrtof Ike Certbral Cirfuiation, dv, fAiuerii.'aJi rL-prinl), 

iPhiUaelplii*. ]&<B. 

' 2S 



33-t 



rtftOtTLATlOW. 



liquid, tlie eeplialorncliidiaii fluid, wliicli ia capable of paaa- 
Liig from the eurfaee of tbe Urain to the Bpinal ctinal^ and 
coinmiiaicjites with (he fluid in the ventricles.' Tliis lie ha* 
confliLsi^'L^Ij demon stratod to he eituated, uot between tlte 
layers of the araclmoid, as waa eapposed by Bicbat, bnt be- 
tween tbo inner layer of this membraEo and the pia mater. 
The communieation between the cranial cavity and tbe siiitml 
canal is very free. This was demonstrated bj earposing the 
dura niater of tbe brain ftod of tbe cord, [naliitig an opening 
in the membranes of tbe cord, eo aa to alluw tbe liquid to 
escape (which it doea in quite a forcible jet), when presfiure 
on llic luembmuee of the brain not only acceleratt'd tbe flow, 
but pressed ont a quantity of the liquid atter all tliat wonid 
escape spontaneously had been evacuated. 

It is easy to see one of tbe physiological nses of this liquid. 
When tbe pressure tif blood in the arteries leading to tlie 
brain is increased, or when there is an obstacle to its return 
by the veins, more or lees congestion takes phtce, and the 
blood forces the liquid from the cranial into the spinal eavity ; 
the reverse taking place when tbe supply of blood to the brain 
16 diminished. The functions of all highly-organized and 
vascular parts seem to require certain variations in the sup- 
ply of blood ; and there ia no reason to suppose that tbo 
brain, in its varied conditiona of activity and repose, ia any 
exception to this general rule, though the pbystological con- 
diltous of its vascularity are not easily studied. 

Tn some hito experimenta by Mr. Durham on the pbyei- 
ology of sleepj tbe comparative vascularity of the nictiiiiges 
of tlic brain atdlU'ereiit times haalieun studied in animale, by 
removing a portion of the skull with a tTL-phine, and supply- 
ing its place by a watch-glaaa cemented to the edges of the 
hone with Canada balsan]. In these experimentSj the author 
demonstrates that tbe vrasels are much more congested <iar. 

' M^CKNDiE, Journal dt Ph^iwhffif, 16SB, tome 7.^ p. £7 et i^., uiil tSST, 
tome vii., p. 60 rt tfq. Sur un tt^ide qui te traavt datu U Cram tt U Oanat 
Vtrilhml Jt VUuiiuM a Jc* .immatt£ Jtmiuni/crm. 



cntcm^Tiox in the ckajtitm. 



336 



ing the activity of tlie braiuj than dming tlio suspcusion of 
its fiuictioua in sleep. TLo liluod-veBsels of the meiiingea 
^ere expoBed freely to view by the operation, and were 
examine*! by the microscope, ivith a low power, as welt as 
ivitli the naked eyo,' From theeo and other observatioas 
Upon tlio human subject, as well as apon the inferior aai- 
maU, there can be no doubt that the blood-vessels within 
the cmnial cavity are Biibject to considerabie phyeiologieal, 
»6 well as pathological vuriatioDS in tension; which is au 
important fact on it* bearing upon certain ibrnis of cerebral 
diaeaiw.' 

PJiysiologists, even before the timeof Haller, had noticed 
allemate movements of expanaion and contraction in the 
brain, connected with the nets of re&piration. Thia is ob- 
served in children before the fontanels are closed, and in 
the adnlt when the brain k exposed by an injury or a 
Biii^cal operation. The movements are, an expansion with 
the act of expimtion, wbieh, iu violent efturtSj is somotimea 
BO considerable as to produce protrusion, and contraction 
Willi ine|iim1i(in. Ma^endie also studied tbese movements, 
which he explained in the following way ; ' WJtli the act of 
expiration, the flow of blood in the arteries ia favore<l» and 
the enrrent in the veins is retarded. If the effort be violent, 
llie valve at the opening of the intc-mal jugnlar may be 
dosed. This act would produce aa espsneion of the brain, 
not from reflux by the veJuSj but from the fact that the flow 
into the cheHt is impeded, and the blood, while paaaing in 
more freely by the arterieR, is raoinentarily confined. With 
inspirafiou, the flow into tiie thorax is matjerially aided, and 
the brain ia in 3onie degree relieved of this expanding force. 



' .iRTBtlt E, Dmnihla, 7'he PRi/tirrlo^j/ 11/ Slerp — Otiy'* HotpUal Seporlt, IStW, 
p. 14*. 

■ See Tol IT., N<jrvoii9 SjsMm, p. 462, tl teg., fqr a. farther «oiuideiwUUQ of 
Ihe conilition of ihe brain during sleep, ibe full discuKsirjQ gC ubicb be)oa(j;a 
propi'riy to ihe nervouB STSlem. 

* SlAQKMMC, lie Vifijiinnce dn moufroimi <!> la poicrine et den effhrlt nir I4 
tircviutioa ia gauff, — Journal dt f^hj/nialaffu, Faria, 1821, tome L, p, 1S2, Kt »eq. 



336 cmcuLATioir. 

Robin has lately noted a peculiarity in the small vessels 
of the brain, spinal cord, and pia mater, wliich is curioua, but 
the physiological function of which is not yet apparent' 
These vessels are surronnded by a thin, amorphous sbeatb, 
which has a diameter of from yiW *** jhs of ^^ ""^^ greater 
than that of the vessel itself. Between this and the blood- 
vessel is a transparent liquid. This structure, wbicb has 
been observed in no other part of the circulatory system, is 
regarded by its discoverer as the commencement of tlie lym- 
phatics of the nervous centres. What effect this disposition 
of the vessels may have upon the facilily with wbicli they 
may become dilated or contracted, it is difficult to determine. 

Circulation in Erectile Tissues. — In the organs of gener- 
ation in botb sexes tbere exists a tissue whicb is subject to 
great increase in volume and rigidity, when in a state of wbat 
is called erection. The parts in which the erectile tissue ex- 
ists are, in the male, the corpora cavernosa of the penis, the 
corpora spongiosa, with the glans penis ; and in the female, 
the corpora cavernosa of the clitoris, the gland of the clitoris, 
and the bulb of the vestibule. In addition, Eouget has lately 
demonstrated the presence of true erectile tissue in the body 
of the uterus, and in a bulb annexed to the ovary of the hu- 
man female, but states that it is not found in tbe inferior 
animals. He has shown by injections that the uterus is 
capable of erection like the penis.* In some other parts, 
such as the nipple and the mucoxis membrane of tlie 
vagina, which are sometimes described as erectile, the pecu- 
liar vascular arrangement which is cbaracteristic of true 
erectile tissues is not found. In the nipple, the hardness 
wliich follows gentle stimulation is simply the result of con- 
traction of the sractoth muscular fibres with whicli this part 

- Robin, Surune l^iniqve Apparimante m propre aux CapSlaira EnefphaJo- 
Rarkidifnt. — Jottrnaldela Pht/iiologte, He., Oct 1889, tome iL, p. 643. 

* itoL'OET, Reclurchcit wur lei Oryana EreelUei de la Frmrru, He. — Jonimdl 
de la Ph^iioloffif, I'aris. 1838, tome L, pp. 820, 479, 73B. 




is largely supplied, and is nimlogoxis to the elevations in the 
follicles of the ekin from tbe same cause, in what is called 
gcx>se-flesh. In the vagitm, congestion niaj occur, as in other 

H niuuons membraijed, bat there is no proper erection. 

^ The vascnhir arrangement in erectile organs, of which the 
penis may he taken as the type, ia peculiar to them, and not 

H ibund in any other part of the circulatory syetem. Taking 
the penis as an example, the arteries, vvhieh have 311 unnsually 
tUiek nittacular coat, after tliey have entered the organ, do not 

H Simply branch and divide dichotonionsly, as in most other 
parts, but send off large nucubers of arboreecent branches, 
which immediately become tortuous, and are distribulecl ia 

■ tbe cavernous and Bpong;y bodies in uiuncrona anastomoeing 
vessels, with hnt a single tUin homogeueous coat, like iho true 

I capillaries. Theae vessels are larger, even, than the arterioles 
.which supply them with blood, some having a diameter 
of from jij to -^ of an iufh.' Tlic cavornoHs bodies have an 
external investment of strong fibrous tissue of considerable 
elasticnty, which eends bands, or trabeculce, into the interior, 

I by which it is divided up into wlls. The traheculad are com- 
posed of fibrous tissua mixed witli a lar^^e number of smooth 
muscular tibros. Tiiese cella lodge the blood-vessels, which 
rnmily lu the tortuous uianner already tudicrated, and titjally 

I terminate in the veins.' Tbe anatomy of the corpora spon- 
giosfl is essentially the same; the only difference being that 
the fibrous envelope and the trabeculffi are more delicate, 
and the celts are of smaller size. 
Without going fully into the mechanism of erection, 
■which comes more properly under the head of generation, it 

I may Im? .stated in genera! terms that during sexual excite* 
' ttoBis, OlisfTvatiOTfi lur la CorutittLti'nt du TtMU ^rtctUf, Tmii, Ift6S, 
* J, Htillcr pfofeaaed to have didcorcrol ■ lyeculiaiit^ in the &rt«ncd i>r erectile 
158*11*8 eonslsliiig in arborescent dirDrtimla from Oic main vesa-el, wilb blind ei- 
Innui'tles. Tlieae be <:u]Iim1 tb>.' JuUcine arCerirA. {Afanufl tie Pli^ioloffic. IVad. 
parjimriian, Pa-ris, ]8fii, iflme i., p. 181.) Bought in liis jicltnimble urticla {lot, 
e.U.) has- gOD« ovor iha V'xperLccienls of Hiiller, aail sliowit coticlujivvly tlint tlie 
BO^»>tlcd tit^li'i-'iiie arU!ric« da noL exist; and that the a|ipearaDicea descrilKd hj 
UiiU^r ore dus to iiu)ierf«vt tUliog gf* \hv <rea««U by tbe icuvctioD. 




S3S 



dKOULA'nOS, 



meut, or when erection occurs from any canae, the thick mns- 
cnlar walla of tbe arteries of supply relax, ATid allow iLe ar- 
terUl preasui-e to distend the cflpacious vessels lodged in tlie 
cells of the carenioas and spongy bodies. This produws tho 
diarat-torlstic change in the volume and position of the organ. 
It is evident that erection dependa npon t!ic pecnhar arrange- 
paent of the blood-vesBels, and is not simply a congestion, 
such as could occur in any vascuhir pai-t. Durinj; erecliim, 
there is not a stasis of hliicid ; but if it continue for any lenptb 
of time, the quantity which passes out of the part by the 
veins ninflt be eqnal to that ■whidi passes in by the arteries. 
If returu by the veins were prevented, gmigrone ■nrotdd inev- 
itably au|)orvene, an ocewrrence which sometinioa takes place 
■vfIicti the root of the jieniB hae become constricted, and if not 
speedily relieved. Erection may be produced in the dead 
body, by preventing reflux by tlie veins, and tilling tho veei 
eela contained in the ceils of the cavernous and fpooj^' bodies 
by injection. It has been shown by Miiller that the penis 
may be made rigid by an injection at a prc4«5uro about equal 
to the pressure of blood in tbe arteries.' 

The mecbauism of erection ol' tho clitoris, iind other 
ereeiile parts, i& essentially the same as in the penis. It is 
seen that in tliis condition, circulation U by no means arrested ; 
and the tortuous vesaels are til!e<l vvjth bloud by an euliwge- 
ment in the caliber of the ^mall arteries of supply. 

Itoiiget has sUowu that the body of the uterus possesses an 
erectile tiuene as perfect aa ttiat of the peniB; and that after 
death the organ may be made to c]ian<re itg furui and |M>si 
tion by injecting the voBsels, when it increases in size alwut 
one-half, rising up, and becoming rigid and erect in the cavity 
of tbe pelvlH." 

This relaxation of the muscular coats of tbe arteries onlj 
csifita for a litne; tonic contraction ocourSj tbe pnpply of 
liluud ii^ dimtuidhed, and the organ returns to it« ordinary 
condition. 

* J. HiTLi-ui, Op. eiL, tome i., p. IBS. " Kocoet, oji. n'A, pp. 838, 89V. 



DEEIVATITE CTBCCLATION. 



330 



Tnder Btimulatioii, tlie inuscutiLr fibres in the coverin;; 
aiid trabefiTilie of tlie cf>rpora cuvemosa anii Gpungioaik. iiiav" 
coiitrict, force the blood from the jjarts, and produce a cer- 
tain amount of rigidity, with dimiiuitiou in size. This ia 
froffOQDtly seen under the influence of cold, which is a pow- 
erful ejtcitant of the uustriped museuSsi- fibres. 

Derivaiive Oircidaitem. — In flome parte of the circulatorj 
Bystern, there exists a direct commumcation between tbe ai'te- 
riee and the rcinft, so that all the blood does not necessarily 
pass throTi^h the iniiiiite veaaela whicli huva been desprilied 
as trne capiUarieB. This pecjuliarity haa been clO'Bely studied 
by M.Sucquot,who wasHrst led to investii^'ate the eubject by 
noticing that by injeoting a very small quantity of ilnid, en- 
tirely insufficient to till all the cApihaHes of a member, it was 
returned by certain of tlie vesns. On using a black, eolidifi- 
able injection, he found that there were certain parts oi' the 
upper and lower extremitiea and the head which became 
colored by the injection, wlnle other parts were not pene- 
trated. l''ollowin«; this out by ditaeetion, he Bliowetl that, in 
the upper extremity, the akin of the tingers and part of tlie 
palm of the hand, and the skin over the olecranon, is provided 
witli vcsaels of eonsiderable size, whidi allowed the fluid in- 
jeeted by the axJLIary artery to pass directly into eonie of 
the vt-ins, wldle in otber parts the veins were entirely empty. 
Extending his researches to the lower extremity, he found 
an&Iugous commnmcationB between the vessela in the knee, 
toes, and parts of tbe solo of the foot. lie also found com- 
municatioae in the noae, cheeks, lips, forehead, and ends of 
the ears, pails which are jiarticularly liable to changes in color 
from congestion of vessels.' 

' J. P. Sdoqdxt, Xtf l» Cireulnthn rf« Simff 4am i» Jfrmirw irf data Itt T<itt 
dt rtTomnu, F&rls, 18sO, p. AD. Ttiougli nil Lbu pIij^Lolvgit^dl deducilom in tliie 
memoir do not seem JuBtiKEiblc, tbe imaiomicii] rj.i:is are uiidoubleil. The prepu- 
ratjoiig. bnvu hei^o eiamint:^ hj a cotDtuiA&ion, of vhwh M. Robin vss a tncnilnor, 
«rblcb ConEmied the ttatctuenis oC M. £ucqueL (On! oommunicaUoa fram BL 
Bobln.) 



340 



CIBCCLATIOM. 



It is evident tliat, under c^rtu-in circQinstanuea, a larger 
quHtitit^ uf blood tlian usual may pass tlirottgli the*e parti 
ivitliont oeceesarily peuetratlng the true capillaries and thus 
exertiut,' a modifying influence upon nutrition. The changes 
which are liable to ocyur in the quuutitv of blood, in the 
force of the heart's action, eti;., may thus take place without 
disturbing the cireulation in the capillaries, a proviaioa whiub 
t!ie functions of the parts would SL-ym to demand.' 

Pulnioiiartf Ch-aiihxi/on. — The vascular system of Uie 
lungs merits the njime, which is frequently applied to it, (if 
the lesser circulation. The right side of the heart acta simul- 
taneously with the left, but is entirely distinct from it, and its 
muscular wnllfi ure very much less powerfuL The puliuo- 
nary artery hna thinner and more distenaible coats than the 
aorta, mid distributes its binod to a single system of capil- 
laries, which are situated very near the heart. We have seen 
that the orifice of the pulmonary artery is provided with 
Valves winch pre\'eiit regnrgltatloii itito the ventricle. In 
the substance of the Inngs^ the pnlmoaary artery is brokea 
Up into capillaries, most of them just large enough to allow 
the passiige of the blood -corpuscle in a single row. These 
VGBsek are provided wilh a fiiu;jle cuat, and form a very cloae 
network surrounding tlie air-cells. From the capillaries, the 
blood is collected by the pulmonary veins and oonTeyed to 

' Bsfoni tb« pubLicDdoTi of the rc»cBrcli«9 of Suqnet, Todd and BowBum nun> 
tioned the jiossiliilit; uf iiupfi comniimicationA bcineen the Arteries utd vaa» ia 
many purls f>f tlic bo<ty, and the pLobitblc csutonoe of Bueh cominutiicAtjona in 
Bomc of the IJBn.i'a, 

"It Ifi not iii]|iralka)iie Ihmt further r6Sf»ro^ maydeteot ■ direct cmnmtitiioatioii 
between arterk-a Btiil veins, cren in. tbssutfi, the ijrunUtet purtornhicU U (umisUed 
trilli [i triK ctLii'iMiLiry [ilr'xus. In tlie ctmcx^tUtcU iicnictLire of boDe-, and th<; dlpl^jo 
of ibc unijiiul bon*!^, it ^i-eiits liigtily prolialjlc! tlmt the aiutiee (2Diumiiiui,ii|« uu- 
mediali^lj n'Uli lIiq vi'ims al mnnv' jKiiDti. Ur, F.ii;^!: [Leetureii wi Jijlcwimltim'^ 
dettcribea a direct (.■oramualcallua between ibc arieniw aud veiBB of iLe (nnj; of 
the bfet, wittiuut an^ inti■^u(^diale c&iiithrf |>1l-ius." — Tcim) utid llatniAK, PAfii- 
nlogval Anatomt/ and Pliytialoffy <tf Mih, AiDcricill ediliou, I'tulikdcljiUiOy 18b^ 
P.U2. 



PULMOHAKT CIRCULATION. 841 

the left auricle. There ia no great dispaiity between the ar- 
teries and veins of the pulmonary system a^ regardu capacity. 
The pulmonary Teins in the human subject are not provided 
with valves. 

The blood in its passage through the lunge does not meet 
with the resistance which is presented in the systemic circu- 
lation. This fact we have often noticed in injecting defibrin- 
ated blood through the lungs of an animal just killed. "We 
have also observed that an injection passes through the lungs 
as easily when they are collapsed as when they are inflated. 
The anatomy of the circulatory system in the lungs and of 
the right side of tlie heart shows that the blood must pass 
through these organs with comparative ease. The power of 
the right ventricle is evidently less than half that of the left, 
and the pnlmonary artery will sustain a much less prtMSure 
than the aorta. 

The two sides of the heart act simultaneously ; and while 
the blood is sent by the left ventricle to the system, it is sent 
\fj the right ventricle to the lungs. Some physiologists have 
endeavored to measure the presssuro of blood in the pulmo- 
nary artery. The only exixiriments which have not involved 
opening the thoracic cavity, an operation wbich must inter- 
fere materially with the pressure of blood in the pnlmonary 
artery, as it does with the general arterial pressure, are those 
of Chauveau and Faivre.' These obtiorvcre nieasured the 
pressure by connecting a canlionieter with a trocar intro- 
duced into the pnlmonary artery of a living horse, through 
.one of the intercostal spaces, and found it to be about one- 
third as great as the pressure in the aorta ; an cstiniate which 
correeponds pretty nearly with the comparative pokvcr of tho 
two ventricles, as deduced from the thickness of tlieir muscu- 
lar walls. 

Anatomy teaches us that the capillaries of the lungs have 
exceedingly delicate walls; and it is evident tliat rupture of 
these vessels from excessive action of the heart would lead to 

hotan, IVaili d«phyUAogie, Paria, 1869, tome iL, p. 257. 



QEIfEBM. R&PtDrnr. 09S 

IsTies of the lungg. onfl prorciiting tlie paasaj^e of Muod. It 
is a view jirettv generally entertained, tliat in nspliyxia the 
non-aerfition. of tlie blood obstructs the pulnioniuy eirfula- 
tioD. We b.ive already cou&idered this subject rather fully 
ill treating,' ot" the general efleets of arrest of respiration on 
I the eirculution. The celebratt'd experimeuts of Bidiat deni- 
oTistrated the passage of blnck blood through the lungs in as- 
phyxia, and its prescnee in the arteiial system. The cxperi- 
meiit6 of Diilton and otiiers have shown that in this cuiidi- 
tioDj the obstruction to the circulation occurs fir&t iu the sys- 
temic cupilhirics, and the distention is propa^sited backward 
through the great vessels and left cfi'vities of the heiut to the 
right side. \STieti the heart ib exposed in fl living animal, 
ftnd artilicial respiration is kept upj arrest of it'spiratiuu 
produces fciiy:orgcment and latmred actiun of both aides. 
ITiere are no ohser\'atioii3 which shvvf that increaae of press- 
ure in the pulmonary art.ery is the first taid immediate result 
of iiaphyxia. It is true^ that aft-er death the right side of the 
heart is engorged; but it is well known, trom observations 
after donth and exptnnieuts on liWng anirtiak,' that tlie 
tonic eotitraction of the arterie* k croinpcteut to empty the 
blood into the reins J and the facts just stated regwdiug the 
iiisufljcieney of the pulmonic sentilunai' valves explahi him' 
the right side of the heart may become engorged as tlie result 
of ob&truetion to the btood-current En the left side. Estiib- 
lished facts seem to sbtiw that asphyxia does not pnmarihj 
afl'ect the pulmunarj' circulation; but that it ls possible fur 
venous blood to pass througii the lunga without undergoing 
arterial i^ation. 



Oeii^TtU JSujfiditt/ of the Oirculation. 

Several questions of considerable pbyaiologieal interest 

arise in connection iviththegeneralriipidity of the circulation: 

1. It would be iiitefestiug to determine, if possible, what 

* See eipertments b^ BLkntNOiK on Che cuuaes of tbe cLrculatioci In Uic rdns. 
PrkiiM £limfniaire de Fhi/mol<>ijie^ Paris, 1833, tome iL, p. &91. 



844 



OmCULATION. 



lenjiftb of time is occupied by tbe blood m its pc 
tlu-uugh the entire circuit of both tbe ledscr and gr 
circulations. 

2. Wliat is the time required for tbe passage of tbe entire 
mass of blood through the heart! 

3, What influence baa tbe number of pulsations of the 
lieart ou the general rapidity of tbe circulation i 

The firijt of these queattous is the oae which bae been 
most satisfactorily answered by experiments on liviag aui- 
luals. In 1S27, Heriiig,' a German physiologist, perlbrtued 
tbe experiment of injecting into tlie jngular vein of a living 
niiiiital a liarmlesa feubstanc-e, wliicb could be easily recog- 
nized by its chemical reaetions, and noted the time which 
elflpspd before it coiild be detected in the blood of tbe vein of 
the opposite side. This gave tbe first correct idea of the rapid- 
ity of tbe circulation ; for though tfie older phyBioIogi&tft, such 
as Ealler, Halee, and KeiU, had studied tbe subject, ibeu- esti- 
mates were founded on calculations which had no accurate 
basis, and gave very different resalts, The experiment of 
Heriiig Is often roughly porlbriiied as a physiological deiiion- 
Btrntion ; and vse have thus bud frequent occasions to Terily, 
in a genei'al way, ita aceurftcj. If, for example, we expoee 
both jugultu:^ of a dogj inject into one a solution of ferroey^^B 
aiddc uf potassium in water, und draw a specimen of blood" 
from the Other with as little loss of time $& poaeible, it will 
be luuiid, that in twenty or thirty seconds at1er the injection, 
tlie salt bus bad time to pass from the jugular to tbo right 
heart, thence to the lungs and letl heart, from tliis through 
tlie capillaries of tbe bund and lace back to tbo jugular on 
tlje opposite BJde. Ita presence can be determined by tbe 
distinct blue color jiroduced on the addition of the perchlo- 
ride of Jrou to tbe serum, if the epcciuien be allowed to 
Btana, or a clear extract of tlie blood may be made by boiling 
with u little sulphate of soda and filtering, treating tbe color- 
\qs& liquid thus obtained with tbe salt of irou. 

' Uii-NR-Epw-iitDa, Lffota mr in Ph^iniogif, tome iv., p. 963, aol* 



OENOIAL EAPTDnr. 



S^ 



Th<? exjieriments of Ilerinj; were evidently con Jucted with 
great cart; and accuracy. lie drew tbe liluod at intervals of 
five eeeondB after the commencement of the injefjtion, and 
tlins, bj repeated observations, aaeertained pretty nearly the 
rapidity of a eirciiit of blood in the flniinal& on which he ex- 
jjeHniGtited. Others have tahen up these jnvcsstJgations, and 
intrwJiiced some niod locations iu the matiipid&tions. Yier- 
ortlt cDUected the l>Iood as It flowed, in little vessels fixed on 
a dibfc revolving at a known rate, which gave a little more 
esiurtue&s to the observations; ' but the method ia essentially 
the eainc as that employed by Ilering', and the results obtain- 
ed by th^e two observere nearly corrospoud. 

The length of time occupied by a portion of blood in 
making a complete circuit of the vascular system, in the hu- 
man subject, is only to be dedueeil from observations on tho 
inlerior anttnals ; but before this application is made, it will 
be well to esamine the objections, if any exist, to the experi- 
mental procedure above described. 

The only objection which could be made is, that a saline 
Bolution, introduced iiito the toireut of the circulation, would 
have a tendency to difl'use itself throughout the whole nuLsa 
of blood, it m!j;ht Im), with considerable rapidity ; and that 
thlB fact ia opposed to the proposition that the aolt, when de- 
tected in a speoiuien of blood drawn from a given vessel, is 
fiimply carried there by the force of the blood-current, This 
objection to the obsei-vfitions of Hering baa been made by 
Atatteuci'i, and is considered by him as fntal to their accu- 
racy.' It certainly is an element which should be takeu into 
act;ount; but from the definite data which have been ob- 
tained conceniin^ the rapidity of the arterial circulation, and 
the inferences which are unavoidable with regard to the ra- 
pidity of the venous circulation, it would seem that the siallno 
aohition must be carried on by the mere rapidity of the arte- 
rial flow to the capillnriea, which are very short, taken up 

' Hci.NB'EimARiw, lae. eU. 

' ILkTtvncci, F!unumiar» Phif»iijW» dt* Corpt Vivanltf p, 3£6 tt ttq. 



3^& 



CrRCULATIOir, 



from tliem, and carried ob hj the veins, and Jbus thmtigli tlm 
entire circuit, before U has had thtw. to dijfuee -iUt^if tuijfi- 
ci^nthj to interfere leltfi the obgervaH(m. It is not apparent 
liyw tbjs ol'jectioTi can be overcome, for a siibstJincc must bo 
ii&ed which will niii witli the blood, otherwise it l'OiiW nut 
pass through the capilhmes. The objection made bv Mat- 
teucci, especially as it does not appear liow the difficuUy cau 
ho obviated, seems an unutcesBary retinement ; for the ques- 
tion itself is not one of vital iiii[K)Ptance, on which depends 
an important physiological principle^ but ainiply one to 
which a tolerably close approximation of the exact trnth is a 
eufficieut niidwer. It is interestiug to know tlmt the Taried 
and complicated actions ivhtcb we have bi>eri studying effect 
a single complete circuit of the h\>y.A in about half a iiiin- 
ute ; but it makes no great difference whether li be fuur or 
live eeconda more or less. In this statement, we must not bo 
understood as denying the value of the closeat possible accu- 
racy in physiological investigations j bat it is evident that 
this accuracy ia important in proportion to the importance 
of tho qiieatiou, tn itself, and in its physiological relations. 

There seems no reusou why, with the 'AmvG resirlctions, 
the results obtained bj Hering should not be accepted, and 
their application, as far ai posgiblej made to the human 
subject. 

Hering found that the rapidity of the circulation ha dif- 
ferent animals was in JiiverBs ratio to their eize, and iu direct 
ratio to the rapidity of the action of the heart. 

The following are the mean resulta in certain of the do- 
mestic sininials, taking the course from jugular to jugular, 
when the blood passea through the hings and through the 
c&pjllarioa of the face and head : 

In the Eorde^ lh« circalnUon U ooconpiished in 27*3 secoiidiL 
" Dog, " "' 16"3 *' 

" Goftt, " " ia-8 " 

" RiibbU, " " OS " ■ 

' Mit-NE-EuwAUiw, loc eU, Yletordt foiind the neoa ni]iidil7 La th« hone 



f 



GENERAL EAPmnT. 347 

Applying these results to the human subject, taking 
into account the size of the body and the rapidity of tlie 
lieart*a action, the duration of the circuit from one jugular 
to the other is estimated at 21*4 seconds, and the general 
arerage through the entire system at 23 seconds. This ia 
umply approximative ; but the results iu the inferior ani- 
mals may be received as very nearly, if not entirely, 
accurate. 

An estimate of the time required for the passage of the 

whole mass of blood through the heart is even less definite 

than the estimate of the general rapidity of the circulation. 

To arrive at any satisfactory result, it is necessary to know tlie 

entire quantity of blood in the body, and the exact quantity 

^irhich paaaes tlux>ugh the heart at each pulsation. If we 

divide the whole mass of blood by the quantity discharged 

from the heart with each systole of the ventricles, we aacer- 

f:£k.in the number of pulsations required for the passage of the 

wTtole mass of blood tlirough the heart ; and, knowing the 

rx «3mber of beats per minute, can ascertain the length of time 

tl:x iia occupied. 

The objection to this kind of estimate is the inncem-acy 
o±" the data respecting the quantity of blood in the system, 
aT-i,^the quantity which passes through the heart with each 
jn^lsation. Nevertheless, an estimate can be made, which, 
it* it be not entirely aecurato, cannot be very far from the 
tr-ta.th. 

The entire quantity of blood, accohling to estimates 
^^'Xia.ich seem to be based on the most reliable data, is aliout 
***^ ^3-eighth the weight of the body, or eighteen pounds in a 
"^^-^fc-n weighing one hundred and forty-fi>ur. The quantity 
**i«»^arged at each ventricular systole is estimated by Valen- 
"*^ at five ounces, and by A'"olkmaini at six ounces.' In 

^~*^-« 18*8 seconds. In experiincntiiig on tlio cninil vein, thh ob.«rrvt:T found 



' ^ drcuUtion in the lower eitremitiu:*, probably (Voni tliu grtalor kngtli of 
^ '^CHcb, occupied from one to tlirec soconils inciru tliuu In the lieail. 

* torn tniBo^ui^, J'hfftioliyUil AHulamv, .Viuerican ciiUiuu, 1B5T, p. lU*. 



u% 



nSCl'LATIOX. 



treating of the capa<.-ity of tlie ilifierent cavities of the h eart , 
it hag' been Duted that the lell rentncle^ when fuSy diimd- 
ed, contains &c*tn five to seven oonoea. AaBBtmttg that at 
each systole tlie left ventricle dischargee all iu blood, except 
perfiftpa B few drops, and that this qaantitT it* »o <«»diB»r¥- 
£ized m&D h five ounces (for in tlie estimated of Kobui aad 
Hiil'eUheim, the cavities were faUy distended, and Dontaiiied 
mure tli&n under the onJ 111317 conditioos of the circulatioo), it 
iroald require fi{t}'-eight pulsations for the paaBage tltnitigli 
the heart of the entire mass of bliM^. Aaenming the paka* 
tioos to be seventT-two per minute, this would occupy aboat 
Jbrty-eiffht seconds^ 

We have given elsewhere the opinions ofTarioaa pl^aio)- 
<^:£t3 on the qnaDtity of blood in the bodj, and tba capaeitj 
of the cardiac cavities, and &ha11 pot disrvae the d i acorJaat 
vie\v$ (ju the " duratioa of the circulation,^ as each ia based 
on different opinions regarding the two essential qoestioosin 
the problem. As the qaaatitv of blood in the bodr kaab- 
ject to certain phT&iological variationsy th«<e flboold be cur- 
responding variations in tlie daration of the circniatioo, 
vrhich it is annecessary to take up follv in tb^ oonBecttoo. 

The alQioat instantaneous action of cotain poisooa, vkidi 
must act through the blood, confirms onr ideas wiOi regard 
to tlie rapidity of the circalation. The interrals befv^en tba 
intTodTictica)of^tDeageDt$(&trvchiiiue for example) into tba 
circulatioi), and tb« characteristic e^Kta OQ tbe ajstem, Iia«v 
been carefuHr noted by Blake,* wbosa obeerratWDB eoinckte 
pretty cloeely in tbcir results with the experiments o£ 
nering. 

The relation of the rapidity of the circoIatiMi to tbe fre- 
quency of tbe tieart'g action k a question of conaideTalilp in- 
terest, which wag not ne^ected in tbe experiineala of H(s 
ring. It is evident that if the charge of btood Gent into the 
arteries be the ^me, or yearly the same, umder all drcain- 

IvL, p. its. 



GEXKRAL nAPIDITT, 



349 



stances, any increase in tUe iiumi>er of pulsations of the heart 
would produce a corresponding uccL'lcnition of the general 
current of blood. But this is a proposition whiiih cannot be 
taken for f^raTited; ami there arc many facts whii.'h fiivoi 
a contrary opinion. It may be ennueiflted as a genenU rule, 
that when the acts of the heart increasti in frequency, they 
ditoiniah in force; M-hlch renders it prubahlo that the veq- 
trtcle 16 most completely dietended and emptied when its ac- 
tion 13 moderately slow. When, howevtr, the pulse is very 
much accelerated, the increased number of pulfiationa of the 
heart uiiglit be sufficient to overbalance tlie dirainiehed force 
of each act, and iueroase the rapidity of the circulation. 

Hering has settled these questions experimentally. Eia 
obaer^-ations were made on boraea by increasing the frequen- 
cy of the pulse, on the one hand, physioloLfically, by exercise, 
and on the other hand, pathologically, by inducing Inflamnia- 
tory action. Hefound, in the ttrat instance, that in a lioree, with 
the heart heating at the rate of 36 per minute, with S respi- 
ratory acts, ferrocyanide of potassium injected into the jugu- 
lar appeared in the vessel on the opposite side after an inter- 
val of from 20 to 25 seconds. By exercise, the number of 
pulsationa was raised to 100 per minute, and the ra]>idity 
of the circulation wim from 15 to 20 aecoiula. The obfierva- 
tions ■were made with an interval of 2+ hours. The same 
results were obtained in other experiments.^ Here there ie 
a considerable increase in the rapidity of the circulation fol- 
lowing a physiological increase in the number of beats of the 
heart ; but the value of each beat ia materially diminished ; 
otherwise the rapidity of the curi'ent ivouhi be iucreased 
about three times, aa the pulse became three times as frequent. 
In ila trauquil action^ with the pulj5e at 3(5, the heart con- 
tracted thirteen tiinc6 during one circuit of blood j while it 
required twenty-nine pulsatioi/S to send the Mood over the 
same couree, after exercise, with the pnUo at 100 - showing a 



' MiL»&EL>wAiu>e, Lepyn* <vr fa J'Atftujtoffie, tome Vf,, p. S'l'I , niKe. 




23 



350 dBCULATION. 

diminntion in the value of the ventricular ayetole of more 
than one-half. 

In animals suffering under iuflammatoiy fever, either 
Bpontaneous or produced by irritants, the same observer 
tbund a diminution in the rapidity of the circulation, accom- 
panying acceleration of the pulse. In one observation, in- 
flammation was produced in the horse by the injection of 
ammonia into the pericardium. At the commencement of the 
experiment, the pulse was from 72 to 84 per minute, and the 
duration of the circulation about 25 secondB. The next day, 
witli the pulse at 90, the circulation was accomplislied in 
from 35 to 40 seconds ; and the day following, with the pulse 
at 100, the rapidity of the circulation was diminiBhed to from 
40 to 45 seconds. 

If we are justified in applying these observations to the 
human subject (and there is no reason why this should not 
be done), it is shown that when the pulse is accelerated in 
disease, the value of the contractions of the heart, as rep- 
resented by the quantity of blood dischai^ed, bears an 
inverse ratio to their number; and is so much diminished 
as absolutely to produce a curreut of less rapidity tlian 
normal. 

With regard to the relations between the rapidity of the 
heart's action and the general rapidity of the circulation, the 
following conclusions may be given as the result of experi- 
mental inquiry: 

1. In pkyaiohgical increase in the number qf heats qfiht 
heart, aa the remit of exercise, far &BampU^ the general circu- 
lation is somewhat increased in rapidUy, though nU in jtro- 
poriion to the increase in the pulse. 

2. In pathological increase of the hea/rfs action, as in 
fSrile movement, the rapidity of the general circulation is 

generally diminished, it may he, to a very great extent. 

3. WTtenever the number of heats of the heart is consioei 
ably increased from any cause, the quantity of Uood dis- 
charged at each ventricular systole is very much diminished^ 




QIBOULAlTOn AFTES DEATB. 



351 



sither from, lack of com/fiefs disteidion^ or fTom iwi)erf^ct 
emptying of the cavities.' 

Pheiwjuen-a m the Circutatmy Sj/stem after DeatTi.—'WG 
do not believe that any one has proven the existence of a 
force in tlie capillaries or the tissues (capillary power) whidi 
materially assists the circulation during life, or produeeB any 
movement immediately after death ; and elifiU not dipcnsa 
farther the extmordinary post-mortjem phenomena of cireti- 
tation, particnlorly those vrhich have been ohserred by Dr. 
Dowler in subjects dead of yellow fever.' But nearly every 
autopsy shows that after death the blood does not roinam 
e«iu»lly diatributed in the arteries, capillanee» and veins. 
Influenced by gravitation, it accumulates in and discolors the 
moat dependent paWs of the body.. The arterica are always 
found euiptyj and all the blood in the body accumulates in 
the venouB aystem and capillaries ; a fact which was observed 
by the anciente. and gave rise to the Mict that the arteries, 
as their name implies, were air-bearing tubes. 

This phenonienon has long engaged the attention of phys- 
iologists, who have attempted to explain it by various 
theories. "W^ithont diacu&sing the views on this subject an- 
terior to our knowledge of the great contractile power of the 
arteries as compared with other vefisels, wc may cite the ex- 
periment of Magendie, already referred to,' as offering: a- 
satisfactory explanation. If the artery and vein of a limb be 
exposed in a living animal, and all the other veesek be tied, 
compression of the artery does not immediately arrest the 
current in the vein, but the blood will continue t-o flow until 
the artery h entirely emptied. The artery, when relieved 

' ThcM great variiittons in the value of iIiq TcntricaUr b;bid]c, iinwinting 
cren, in tlic expcfiment on the healthy animAl, to a dhiitniitioD of on&hALF, «b tho 
rwullof ciereiHc, atifiiv theiitrcertaiiitT of the htksie nf thopecstiintilM witb regard 
u> the time required for tha fiitirc- miias of bloiid tn pass thniilph Ihs hi-art, whii^li 
ll.n> calmlutL'd from the entire quantitjp of blood, the qumitilY digclmrj^'d from iba 
bean (tt eix<.-1i puls&tion, aud the number of pulsations per imiDute. 

* 1i%e ptgc iQ&. 



853 OIBCULATION. 

from the dktendini; force of the heart, ruacte ou itd cuntenta 
by virtue of its contractile coat, and completely empties itself 
of blood. An action similar to this takes place after death 
throughout the entire arterial system. The vessels react on 
their contents, and gradually force all the blood into and 
through the capillaries, which are very short, to the veins, 
which are capacious, distensible, and bnt slightly contractile. 
This begins immediately after death, while the irritability of 
the muscular coat of the arteries remains, and is seconded by 
the subsequent cadaveric rigidity, which affects all the in- 
voluntary, as well as the voluntary muscular fibres. Once in 
the venous system, the blood cannot return on account of the 
valves. Thus after death the blood is found in the veins and 
capillaries of dependent parts of the body. 






CHAPTER X. 



HESPIBATrOH", 

nic-tat iconiudentiaiiis — PliyEbtcigiuil &tifttotiiT oCi\ic KsjAmtory organs — Ri'spi- 
n.tarj morementB of the larynx— Epiglcttia^ — Tiudiui tuni brunuhinl tulxifi^ 
Parencbynia of the lucg^— Carbon aceo us m«ller in the lung*— Motc men te ftt 
rcspinttioti^Iagpinitioii— UuK'lrs of itiNpini4ioa— Action of the dlapiiragiD — 
Action of the ecaleri]— Iiiiercflstftl miisolfH — LsTatorea (.■oataruQi'^Auiillarj' 
muflcles ofingpiratJwi, , 



The eharaetere of the blood are by no meatiB identical in 
tbe great divisions of the vascular system ; but thus far, plij"*- 
iologiets baye been able to inv^tigate only tbe differences 
which esiflt between ai'tenal and venous blood ; for tbe capil- 
hiries are bo sliort, comniunicHting directly with tbe arteiicB 
on tlie one eide and the veins on the other, that it liaa been 
imposaiblo to obtain a specimen of blood whicli can be said 
to beloni* to this system. In the eapillaries, however, the 
^iiiitritive fltiid, which ia identical in all parte of the arterial 
lystem, ondergoea a rifTtiflrkable change, rendering it nnfit 
'for nutrition. It is then known as veiicma blood; and, 
UB we have seen, tlie only office of the veins ia to carry it 
baet to the right aide of tbe heart, to be sent to the lunga, 
where it loses the vitiating materials it has collected in the 
tisaueSj takes in a fresh supply of the viWfyiiig osygeoj and 
goes to the left or systemic heart, again prepared for nutri- 
tion. As tbe processes of mitriiion vary in ditferent parte of 
.the organism, necessarily, there are corresponding variations 




3£4 



BffiPKAnoS. 



in ffa« compoatioii of the blood throogbcHit the 
Bjrsteoi. 

The imi>orUDt prind^es which *r6 gi^en off fay tfas 
Im^ are exhaled from the tiJood ; And the gK -rnhiA dkmp- 
pews finxn the air is ftbgorb«d br the blood, wmafy br h 
ODii|iaBciikr ekmeaate. 

A proper supply of oxygen is indispeaMhie to BBtrituB,^ 
Aod even to the oompandTdy mechanical praoe» of i 
tioo ; bat it is no leds neeeaBary to the vital fattttmyt that 
eariwnic acid, whic^ the blood aeqairK in the titEaea, aknld 
be given oS. 

BespiratioQ may be defined ctrictly as the proeoi by 
which the Tariooa tiwiMS asd organs receire oxjgea. 

As it 13 ahnoet exdnsiTely throogfa the Uiood that the 
tiinue and o^&ns &re &nppli<ed vith oxjgeo, aikd a& the 
Uood i«ceive» and exli«k6 mo^t of the carbonic acid, the »• 
qaiatoiy prooese may be aaid to oonaist diiedy in the fhangri 
of venoos into arterial blood. Bat experiments have danam- 
•trated that the tiseues chemadlTB^ detached from the body 
and jdaoed in an atmoapbere of ox^eB, wfll ^noiii Aia gai 
and exhale carbonic add.' TJnd^ tfaeae circiLmstaBoeB, they 
cert^nly rehire, and it is eridoit. th««£)re, that in this 
pnoeH the interrention of the blood is not an abatrfnia 
necesitT. 

The tide ofair in the Innes does not ooottirate reepiratJon, 
as we now onderetand it. The^ oigaiia only Eerve to fitciH- 
tate the intjodaction of air into tbe blood, and tf^e e:xhalattt» 
of cariMuic acad. If theayvtczn bedninedof blood, cr if the 
blood be leodcnd incapable of interchanging ita gases with 
dwair, Hipiiation eeasea, and all the pbeoomoia of asphyxia 
are presented, Uhw^ air be inttodnced into the faaigs with 



■ciiea^ 

A« Md Mn&*r >«^ fi«* Um^ ail ONriMB-M 
,U»^*«LiL,|T.»T,4».> 






OESKEAL. CONBIDEHAllOSa. 



855 



tie ntmoet regularity. It must bo rememhered that the e^ 
»entiiil processes of respiration take place iit all the tissuea 
»nd organs of the sjstem, aad not in the lungs. Eeepiratiyn 
IS a process Bimilar to what nre known as the processes ot 
nutrition ; and although it is miu-b mure active and uniform, 
aa tar as its producta are eoiietrnetl, than the ordinary nutri- 
tive fltts, it ifl inBei)flrHl»ly connected with, and strictly a part 
of the generiJ process. Aa in the nutrition of the eiilistance 
of tissues, certain pHtieiples of the blood, plaemine and 
serine, for example, unitiid with inorganic-: principles, are need 
up, transformed into the tissue itaelf, finally changed iuto 
escrementioua products, Bueh as urea or cholestenne, and dis- 
charged from the bodj', so the oxygen of the hlood ia apprO' 
priated. and carbonic aeid, which is an excrenientitious prod- 
uct, produced whenever tiseues are wont out and regener- 
ated. There is a necetisary and inBepiu'ahle connection be- 
tween all these processes; and they must be considered, not 
as distinct functions, but a& different parts of the one great 
functiou of nutrition. As wo are aa yet unable to follow out 
all the changee wbich take place between the appropriation 
of nutritive materials from the blood, and the production of 
efl'ete or excrementitious sub&tances, it id irapossible to say 
precisely how tlie oxygen is used by the tisaues, and how the 
carbniuic atid la produced. We only know that more or lese 
oiygeti is necessary to the nutntion of all tiseuea, in all ani- 
mals, high or low in the scale, and that they produce a cer- 
tain quantity of earbouie acid. The fact that oxygen is con- 
sumed with much greater rapidity than any other nutritive 
principle, and that the production of carbonic acid ia corre- 
spondingly active, as cumpared with other efi'ete products, 
points pretty conclusively to a connection between the ab- 
sorption of the one principle and the production of the other 
In asphyxia, iudeeil, it is difficult to say which du&troya 
life, the absence of oxj-gen or the accumulation of carbonic 
acid. 

In some of the lowest of the inferior animals, there ia 



356 



KKSPrttATIOS. 



DO sjiecial respiratory organ, tlie intercbange of gises being 
^Ifectcsi tlii\.<ugli tbe geaerul surface. Rigber in tho a&Uaal 
ficalti, gpectal oi^n£ are fonnd, wbicli are called gills, wben 
the aaimals live under water and respire (he air whidi i& in 
solution in the water^ and Inngs, when the air ii iDtrodaced 
in its gaseous form.' Animals pOBseeaed of Inngs hare a lol- 
erably-perfect ciroolatorT ap^^aratas, so that the blood ia 
made to paga eontinua.lU'' through the respiiatmy organa, In 
the human subject aud wann-hlooded animals gmeraUj^tbe 
lungs arc verv complex, and preBcnt an immense soriace 
bj ^hich the blo<xl ia esq»5ed to the air, onlv separated frutn 
it by a delicate permeable toembraoe, Th«&e animals are 
likewise provided with a special heart, which has the ddtj of 
carryiog on the pulmijoarr circulation. Tliongh re^iratioai 
is carried on to Bome extent bj the general surfeoe, the loiif^ 
am the important and essential organs in vhidi the inter- 
ehange of gases tates place- 

The essential conditions for respiration in animals which 
have a circuUting nutritive flaid are: airattdhfood,9epa- 
raf^ hy a niemhrane iehicK ipiil aHoie the pa*»ag« t^ffotet. 
The effete pTi>duct$ of respiration in the blood pass ont and 
vitiate the air. The air is deprived of a certain portioD of ita 
oxygen, which payees iato the blood, to be ooaTcred to 
the ti^ue:^ Thus the air luust be changed to euppljr fn;^ 
oxygen and get rid of the carbonic acid. The npidiihr of 
this change is in jirojKirttoD to the notritiTe acttvitj of the 
lUiimol and the rapidlt v of the cirenlation of the bloods* 



' IlW-i-til tw<V w iftip i Ink tlw MT i» dispaDimUd iVva^hsM A* WgM^^B 
br ■■ Byttam vt nHMWing abta (irae anmes), or tncM^ tad im |ii illwJij 9- 
I]ruf>nji«j dirKtlT b* the liasiHs, wiilunii tue tnvmiiaB gf ifae Un4L 

> Tbe icADaer in «bicb this chui^ of air u ^KftA m ^dflbiHtdHHicf 
amaata hw limw aae <rf the a>o^hitcfrsaagfiAjonaiatKnfantift^jiUki^ 
Uufdj hM Aoww bo», V T pM» froTO the lo«« 10 A* Ughv «4en cf h^ 
Dub^uid the ftmeiam bc w sore moirt, t AriOm^hbm ^kM ^aet 
PmctHM wUA m Ike lonat unrf* lun •• i^MMi mrffaat, «m put, ■• IIm 

■re uaig&od M flpacU wpai, vtefa « bnu^ W ■ H^ 11 Mr nf dgyrfep 



AXATOMT O-F TOE BKPIRATOET ORGiN&, 6cl 

In treating ia detail of tlie function of resijiration, it will 
be convenieut to make tlio following division of the Bubjett: 

1. Tbe mechanical phenomena of reepimtion ; or the pro- 
ceases bjr which the freoh air is introduced into the lun^ 
(tnspiratMrC), and the vitiated air is expelled {expiration). 

9, The changes which the air uudergoea in reapiration, 

3. The changes which the blood undergoes in respiration 

4. The relations of tlie cooBnitiption of oxygen and the 
production of carbonic acid to the general process of nutri- 
tioti. 

5. The respiratorv sense ; a want, on the pait of the Bjs- 
tem, which indnees tLe resiHratory acts {^atotn de rMpirer). 

6. C'utiineous respiration. 
1. Asphyxia. 

Tlie Btudj of these questions will be facilitated by a brief 
consideration of some points in tbe anatomj of the respira- 
tory organs. 

Pkifsiologioal AnnUfmy qf the JRespiraio/y Orgam. 

Passing baokward from tbe mouth to tbe pharynx, two 
openings present themselves: one, posteriorly, which leads to 
the cesophagus, and one, anteriorly, the opening of the larynx, 
which is the commencement of tbepsiseages devoted eiolu- 
fetvely to respiration. The cons.trnetion of the tcaaphagus and 
tbe air-tubes 19 entirely different, Tbe <eeophagu6 is fiaccld, 
and destined to receive and convey to the stomatih the ar- 
ticles of food which are introduced L»y the eonBtrictions of the 
muscles above, Tbe trachoa and its raniificationfi are exclu- 
sively for the passa^ of air, which is^ taken in by a suotion 
force producud by tlie enlargement of the thorax. The act 
of inhalation requires ibat tlie tubes should be kept open by 



TD«it. T!ie peffftiiion of oi^iinizaiiii'ti ia ihu bigh«r' animals Bcema to conaiBt in 
iJic raul Li plication of oi^inii, f'lr the m^K eOlcii^tit perCuniiAnci? of Che varionj 
FuUCtirtTU. 



35S 



BESproATiny. 



■walls euflScicDtly rigid to rceiBt the external prcBBure of the 
air. 

Commencing with the larjiix, it is seen that the cflrtilag;es 
of which it is composed are sufficiently rif,nil and iiiiyield- 
ing to reaiat the preesiire produced hy any iiifi^tratory eflbrt. 
Across its Bnpcrior opening are the vocal chords, which are 
four in number, and haTC a direction from before backward. 
The two superior are cnlled the fulae vocal thords, because 
they are not concerned in the proditetton of the voice. The 
two inferior are tlie triio vocal chords. They are liganten- 
tuufi hands covered by folds of mucous membrane, whit-li is 
quite thick on the superior chords, and very tliiii and deli- 
cate on the inferior. Anteriorly, they are attiitthed to a tixcd 
point between the thyroid cartilageiS, and pofiteriorly, to tbc 
movable arytenoid cartilages. Mr iu admitted to the 
trachea through an opening between the chords, which is 
called the riina glottidis. Little mnscles^ arising trom the 
thyrtijd and cricoid, and attached to (he arytenoid cartilages, 
are capable of separating and approximating the points to 
which the vocal chords are attached pystoriorly, so as to 
open and close the rinia glottidiei. 

If the glottis be exposed in n living anLmal, certain regu- 
lar niovoTJienta are presented which are fiynchronoue with 
t!ie acts of respiration. The larynx is widely opened at each 
mspiration by the action of the mnsclea referred to above, bo 
that the air has a free entrance to the trachea. At the ter- 
jnination of the inspiratory act, the&o muscles ar© relft.Ted, 
the vocal chords fall together by their own elasticity, and in 
eapiratioa, the chink of the glottis returns to the condition 
of a narrow slit. Tliese respiratory movements of the glottis 
are constant, and esgential to the introduction of air in 
proper quantity to the lungs. The expulsion of air from the 
lungs is rather a passive process, and tends in itself to sepa- 
rate the vocal chorda; but inspiration, which is active and 
more violent, were it not for the uiovements of the glottis, 
would hftvo a tendency to draw the vocal chords t«igether. 



KESPDtATORr ilOVElTENTS OP THE GLOTTIS. 



35i1 



Tlie ronst'les wliicli are engaged m producing tliefic movC' 
menta are auiiuated hy the inferior laryngeal branches of 
tlie pnenmogfifitnc aerves. If these nerves be divided, the 
movemeiitfi of the glottis are arrested, and resi>iration U 
very seriously intertered with. This is jiarticularly marked 
ill young aainiala, in which the walla of the larynx are com- 
paratively yieldiug't when the operation la frequently followed 
by immediate death from suifocation. The movuineuts of 
the glottia enable ub to undfratand how foreign bodies of 
considerable size are sometimes accidentally introduced into 
the n{r-pa;^ages. 

The respiratory movements of the larynx are entirely dis- 
tinct from those engaged in the production of tlie voicej and 
are simply for the puriHKe of facilitating the entrance of air 
in injspi ration. 

Attached to the anterior portion of the larynx ia the epi- 
glottis; a little leaf-fthajied lamella of tibro-t^artifage, which, 
during ordinary i-eapiration, projects upward, and lies against 
the posterior portion of the tongue. During the act of de- 
glutition, respiration is raometitarily intGirinited, and the alr- 
pftS-'^ages are protected by the tongue, which presses baekwiird 
tarrj'ing the epiglottis before it, cooipietely closing the open- 
ing of the larynx. Physiologists have iiueationed whet!ier 
the epiglottis be necessary for the cumidete protection of the 
air-paaaages ; andj repeating the experiments of Magendie, it 
haa been fretiuently removed from the lower animals without 
apparently interfering with the proper deglutition of solids 
or liquidii. We have been Batisfied from actual experiment 
that a dog will swallow liquids and solids immediately atter 
tlie ablation of the epiglottis, without allowing any to pa$a 
into the trachea ; but it becomes a question whether this es- 
perlnierit can be abftolutely applied to the human subject. 
In a case of entire lose of the epiglottis, which was observed 
in the Bellevna Hospital^ tha patient experienced alight 
difficulty in awallowiug, from the passage of little parti- 
cles into the larynx, which proiluced cough. Tbid caae 




360 



BESPmATION. 



seemed to ebow that tlie presence of tTie epiglottis, ia tlie 
human subject at least, is nece-sear? to the complete prote^^ 
tion of tlie air-passages in deglutition/ ^H 

Passing down the neck tVoin tiie larynx toward the lungs, 
is a tube, from four to four and a half inches in length, and 
about three-quarters of an inch in diameter, whith is called 
the tracLiea, It is provided with cartiliYginous ring?, from 
sixteen to twentj in number, which partially surround the_ 
tuhe, leaving about one-tLird of its posterior portion occupied 
by fibrous tissue, mised with a eertaia number of unstxiped 
mu&cular libres. Fae^ing into the chest, tlie traoiiea divides 
into tlie two primitive hrouclii ; the right being shorter, 
larger, and more horizontal than the left. These tubes, pro- 
vided, like tlie trachea, with imperfect cartllaginooa rings, 
enter the lungrf, divide? and subdivide, until the minute raini- 
ficfttions of the bronchial tree open directly into the air-c^lU, 
At^er penetrating the lungs, the eartihiges bceotne hteaular, 
and are in the fonn of angular plates, which ave bo disponed 
as to completely encircle the tubes. lu tubes of very small 
size, these plates are less numerous than in the larger bn^nclii, 
until in tuh*^ of a less diauieter than -^ of an inch, they ar^ 
lost altogether. ^| 

The walls of the trachea and bronchial tnfiee are com- 
posed of two distinct meiubranee: an external membrane, 
between the layers of which the cartilages are situated, and a 
lining mucous membrane. The external membrane is com- 
[josed of inelastic and elastic fibrous tissue. Posteriorly, in 
the space not covered by cartilaginous rings, these l!bres are 
mixed with a certain number of Unstriped or involuntary 
muscular iibres, which exist in two layers: a thick interuul 
layer, in wliich the tibres are transverse, and a thinner hmgi- 
tuflinal layer, which is eirtemal. This collection of muscular 
fibres is sometimes called the trachealia muscle. Tliruughout 

' Thin rcmarknbLc cnae, In wMrh the epi^'loltis hniI elDuglicd entire); uMtj 
laanng Uie piirta cowipletclj cicatriieii, as demo us 1 rated by a Iwyngoscopke eiuk 
badcin, will be gif«n in txtmta in coimution vrlib the sul^ect of d^LutitiaiL 



FABENOHTUA OF THK LPNOS. 



301 



lh« entire system ot" broccliiiLl tubes, there are cifcular fasciculi 
of mnscular fibres Ijing just beneath the mucous membrane, 
wilb a number uf longitudinal elastic tibree. The character 
nf the bronchi abruptly changes in tubes leaa than -^ of an 
inch in diameter. They loae the cnrtilaginoua riugSj and the 
external and tbe mucous membranes l>ecome so do^ely unitcil 
that they can no longer be Bepnrated by dissection. The 
. circular muacular fibres c-ontinue domi to the iiir-cella. The 
mueoua meuibrane is smooth, covered by ciliated epttlieliuin, 
the movements of the cilia being always from within out^ 
"wanl, and it ia provided with iinmt;rous nmcoue glsnde. These 
glands are of the racemose variety, and in the hirynx are v( 
considemble size. In the trachea and bronchi, racemose 
glands exist in tlie membrane on tlie posterior eurfauo uf 
the tubes ; but anteriorly are small ibJlielcB, terminating in 
a single, and sometimea a double, blind extremity. These 
follicles are lost in tubes leaa tban -^-^ of au inch in diameter. 
It ia the anatomy of the parenchyma of the lungs which 
piDsdeege^ the litogt physlijto^ical interest, for here the essentiul 
processes of respiration tal^e place. '\Vhen moderately in- 
flated, the limgs have the appearance of irregular eunes» with 
rounded apices, and concave bases resting upon the diaphragui. 
They fill all of tiie cavity of the chest which is not occujiieJ 
by the heart and great vessels, and are com[detely separated 
from each other by the mediastinuni. In the human subject, 
the lungs arc not attached to the thoracic walla, but are 
closely applied to them, each covered by a reflection of the 
eeroub membrane i^hitb lines the cavity on the torresjionding 
aide. Thua they :]ecessarily follow the movements of ex- 
panaion and contraction of the thorax. Deep fissures divide 
the right lung into three lobes, and the left lung into two. 
The Biirface of the lungs is divided into irregularly polygonal 
Bpaces, from } of au inch to an inch in diameter, which mark 
what are Bometimes called the pulmonary lobules, though 
ihie term is incorrect, na each of these divisions includea 
qtiite a number of the true lobules. 



36-3 



RESriEATIOS. 



Flf 10. 



>. 



Following out the bruncliia! tubca from the diflmeter of 
^ of an inch, the smallest, which are tVom -rh to y, of nn 
inch in diameter, open into s. coUection of oblong Tesicles, 

■wliich are the air- 
cells. Each eolleo- 
tion of vesicles cun- 
Btilutes one of ihe 
true luilinonary lo- 
bules, and ifl from 
^ to ,^ of an inch 
in diameter. After 
entering the lobule, 
the tube Ibrms a sort 
of tortuons central 
canal, Bending oii' 
bmuchea which ter- 
niinflte in gjronps of 
from eight to fittecn 
puluionary cells. 
The cetU are a little 
deejier than they are 
wide, and have a 
rounded blind ex- 
trcoiity, Some are 
smooth, but many 
are mnrlced bv litllt) 
eircnlar constrictions, or mgie. In the healthy hmg of the 
adnlt, alter death, they meaenre from j^r *o ytB or i,^ of an 
inch in diameter, but arc cnpable of verv ^at distention. 
The smallest cells are in tlie deep portions of the lungs, and 
the lai^cst are situated near the eurface. By wctione of lung 
irvflated and dried, Magendie demon stratetl, a Dumber of 
years ago, that there is a considerable variation in the size 
of liie cells at diJfcrent periods of life ; that the smallest 
cells are found in young children, and that they pmgrt»- 



■ frmnp 



FA&SHCimCA OF TBE I.CNQS. 



363 



eivcly increase in size with age.' The tiir-cells tire Bur- 
rouuded bj' a great nuinher of elastic fibres, which do not 
form distinct bundles for each cell, hut annatomose freely' 
with each other, m that the same filjres belong tt> two of 
more. This structui^ is peculiar to the parenchyma of the 
Iuug3, and gtres these organs their great diatensibility and 
elasticity, properties which play an important part in ex- 
pelling the air frora the chest, fi3 a consequence simply of 
ce&aation of the action of the inspiratory muscles. Inter- 
woren with these elastic fibres is the richest plexme of 
capillrtry blood-vesBela found in the economy. The veasefe 
are larger than the capillaries in other situations, and the 
plexua is bo close tijat the spaeea between them are narrower 
than the voesels th<-mselves. When distended, the blood-ves- 
eeh form the greater part of the walls of the celle. 

There Is some diflerenee of opinion among anatomistB with 
regard to the lining of the air-cells. Some are of the opinion, 
with Raiuey and ilandl, that the mncona membrane, and 
even the opithelioju, cease in the small bronchial tubes, and 
the blood-vessote in the cells are uncovered. The presence of 
pavement-epithelium has been demonstrated, however, in the 
cells, but the scales are detached soon after death, and cannot 
always be ob&erved. All who contend for the esistenco of a 
.mucous membrane admit that it is of excessive tenuity. 
IWbiu, KoIHker, and others have demonstrated in the air- 
cells very tlitn scales of psvement-epit helium, trotii -^-^ to 
y p'tij of an inch in diameter, which are applied directly to the 
walls of the blood-vessels.' The epithelium here does not 
poeui to be regnlarly deerjiiamated, as in other sitnations. 
Kxamiiiation of injected specimens ahows that the blood-ves- 
sels are so situated between the cells, that the blood in the 
greater part of their circumference is exposed to the action 
of tlie air. 

' Maoejipee, J/fmw'rs *w la Structure Ja prmmon 4e T HvnuM.—Jfttirwi! -fr 
Pkiflioiofni; 1921, loniB i., p. VS. 

• KoLiiKEsi, AftniMl o/ Hvinan. Mierotixpie Aitaiom), Londun, I8ll(l, p. aST ; 
imJ FoDfTJEt, Hialoinffie IltUHatn^ Puis, 18fl4, p. 286. 



364 



EESPIHATION. 



Tbe entire maMof venoiLshlood isdii^trilmted in the lungs 
bv the pulmonary artery fortlie purposes of aeration. Arto- 
ri»l blood 13 conveyed to these organs by the lironchial arte- 
ries, wliicli ramify and eiibdiv-ide oti the bronchial tubee. and 
fallow tlicir course into the luuga, for tbe nouriebmeDt of 
tlieee parts. It ts posaible that the tissue of tlie lungs may 
receive some nouriahmout from the blood conveyed there by 
the pulmonary artery ; but as this vessel does not send any 
branches to the bromibial tubes, it Is undoubtedly the bron- 
chial arteries which supply tbe material for their nutrition 
and the eeerction of the motous glands. This h on<' of tbe 
anatomical rea&on* why irtllaniniatory conditions of the bron- 
chial tubea do not extend to the parenchyma of tbe lungs, and 
vice verm. 

Tlie foregoing anatomical sketch shows tbe admirable 
adaptation of the trachea and bronchial tubea to the pas- 
sage of tlie air by inspiration to tiie deep portions of the 
lnng«, and the favorable ca>nditioDB which it there tueetji with 
for an in torch aoge of the elements of the air and blood. It 
ie als^ evident, from the enormous number of air-cells, that 
the respiratory Buxl'ace must be immense.' 

Carbonaceoiia Matter -hi the Luiuje. — The lungs of niogt 
of the inferior animals and the human »ubjec-t, in eai-ly life, 
have a uniform rose tint; but in the adult, and particularly 
in old age, ihey contain a greater or less quantity of black 
matter, which may exist in little masses, deposited here and 
there in the pulmonary striicturc, or forming linw on the 



* Bales cstimiled the combined Aaif&f«or Uie tu-M^ at 289 squaiv feet 
{Stalieal &*<itf, sOE. i., p. 2-12); Kdll lit 21,90B atiuart inches (&»(ijfli on Bmxnt 
Parla of the Aiiiiaal (Ki.-oru»Mf, \u 1-^); nnd lJ(.-lK'rliiiliD a.K I, £00 square fei?t 
(Di-Bqusos'h Human Phxpnologfi, ISfiQ, toI, L, p. £78). There are not Bufficit.'nl 
dut& oil l}iie point Tor us to fonu anj thing IJlce & reliable cstirojttr. ti it 
Btmpl; i;v^iJ(»Dt tliftC thu t'&tuiii of tmrfuue eduhI be rerf gcenL In puaiot; fVom 
tbe lOTTCr '.o ititf Li);bcr ordere of animaLs, i^ is sops ibat Naiurv prus-iilos for 
the nuoc^fi^y ofDa iDcr^asein tbe activity of tlic rc^pinittti^ jiroci^ by a dimin 
iabed size ondA m a lti[vli cation ol' the ur-ciJLa. 



CULRnOIT&.C7EOUB HATTKE IN TirE r.UNOe. 



3(15 



eurf«t!e of the organs, Tlie deposit is. generally most abun- 
dant at tlie eiimmit of tbe lungs. Tbie matter also exista in 
tlio Ivinpliatic gUnde connected with tbe pulnnniary struc- 
ture, which are eonietiraes called the 'Mirondiinl glauds." 
Tho nature of this deposit baa been tlie subject of cmiisider- 
able discussion. Some have aupposeil that it waa curiuected 
with melanotic deposits, and consiatfHl of ordmary pigmentary 
matter ; but ebemicnl invesTig,itioii& bave now pretty couclu- 
sively deuionatrated that it in notliing more nor lejsa tlian 
carbon. It exjfits in great abnndaiice in the laugs ot'minerB, 
who inhale great quaatities of CBrboiiaceous jjarticles, and of 
those who arc much exposed tu tbc inhalation of smoke. 
Tbeae I'acts, taken in connection with its al)&cne.e in young 
jjerBuiis and the inferior animals, and its small (quantity, even 
in old Dge, in those who inliabit villages aod are nut exjwsed 
to a smoky atmosphere, point to its iutruductjon fi'oin with- 
out. The subject bae been most completely iind ably inves- 
tigated by Robin, who has corne tu the cunclueion that the 
matter ia really carbon ; thai it is iutrodueed iu tine partielea 
in the in&pired air,, and that, once in the lungs, it penetrates 
the tissue, not by absorption, but l)y ineKbanieal action, until it 
tindfi its way tMjneatli the pleura and into the intercellular 
eubstauee. Front tlie i'aet that carbon is insoluble, its penetra- 
tion must be mechanical ; and, wlieii found in the lymphatic 
glands, it ifi carritd there by the abtjorbent vessels. When 
it huB peuetruted the substance of the tiseues, it can no more 
be removed than the tattooing beneath the Bkin ; indeed, the 
deposition in the lunga may be compared very aptly to the 
process of tattooing. 

The mechanism of it& introduction is the fallowing : The 
little sharp, almost microscopic, partic-lca are inhaled and 
come in contact with the delicate wall 3 of the air-cells, in 
■which tbey are imbeddeil under a certain pressure. "Wlien 
any part is subject to pres-surc^ it is well kmjwu that it gives 
way by absurption, the pressure facilitating tbe removal of 

wom-oiit matter, but interfering with the deposition of new 
84 



366 



BESPffiATION. 



mateniil. These partidea thti9 penetrate tlic I'lng sttbetajtce, 
from wlitch they can never lie reuiovefl. They may find 
tbeir vaj into the lymphatic vessels, but become Used, ia the 
lymphatic glands, in wliich thu quantity is alwa}-8 propop- 
tionate to that which exists in the liings. It liaa been shown 
that the particles introduced under the &kin in tflttooingmav 
also be taken up by the lyniphnrieSj but are arrested and 
fixed in the glands.' 

There ia no ground tor the hypothesis tliat the cftrbona- 
ceoiis niatter of the Innga and hronehjal glands ts deposited 
as a residue of combustion of the hydrocarbons, in the proceee 
of rctipiration, 

Movemmis qf JfespircUi&n. 

In man and the warra-hloofied animals generally, the 
lungs attain their greatest degree of dcTelopmeut, the sur- 
face which is exposed to the atraospliere ie relatively great- 
est, and it is in these organs that nea.r3y all of the procere of 
interchange of gases takes place. In all aaiiuuU of this class, 
inapiratiun takes place aa a coasequence of enlargement uf 
the thoracic cavity, and the entrance of a quantity nf air 
through the respiratory piissagee corresponding to the in- 
ereased capacity of the Uings. In the mammalia, The chest \a 
enlarged by the action of muscles; and in ordinary rwpi- 
ration, inspiration ia an active process, wlule expiration is 
comparatively passive. In many birds, the chest i» com- 
pressed by niu&ciilar action in expiration, and inspiration ia 
efi'ected in a measure by elasiic ligamenta. In both claaiea, 
the air is drawn into the chest to supply the space prodaced 
by its enlai^meiit* In some of the lower orders of anirnals 
■which have no riha or &temnm, or in wliich the tliorax ig 
immovable and there exists no division between its cavity 
and the abdomen, the air is forced into the Inngf' by an act 
like deglutition. In these auiiuals (frogs, lizimls, turtles, 

' Tbo resolts of the tavcstigatiDna ot Rob^D are (o b« rouoil ill the CAbnit 
Aiialomi^tit, by Roam aad Vebdejl, tomo Ul., p. 605 «l tof. 



ETTBfrRATIOJr, 



seT 



etc) the respiratory acta are very mfrequeiit ; and in aome, 
the oiidftticn of the Llowl is more eff'ectnally performed by 
tlie geueral siirface than by the lungs. 

A glance at the physiological anatomy of the thorax in 
the human subject makes it evident that the aelion of certain 
musi'les will considerably increase its ca|jii«ity. In the flrat 
place, the diaphragm mounts up into its cavity in the form 
of a vaulted arch. By contraction of its fibred, it is brought 
nearer a plane, and thua the vertical diameter of the thorax 
is increased. The -walla of the thorax are formed by the 
dorsal vertebriE and ribs posteriorly, by the iipj»er ten ribs 
laterally, and by the etemuni and costal cartilages anteriorly. 
The direction of the rlbe, their mode of connection with the 
etemum by the costal cartilaj^es, and their articulation with 
the vertebral column, are eiicli that by their moveiueots the 
antero-postcrior and transverse diameters of the cbeet maybe 
considerably modified* 



The ribs are somewhat twisted upon tbemaelves, and have 
a general direction forward and downward. The first rib ie 
nearly horizontal, but the obliquity progressively increaBea 
trom tlie upper to the lower parts i>f the chest. Tliey arc 
articulated with the bodies of the vertebra-, so as to allow 
of considerable motion. The upper seven ribs are attached 
by the costal cartilagea to the etcrnnm, theae cnrtilages run- 
ning upward and inward. Tlie cai'tilnges of the eighth, 
ninth, and tenth rtba arc joined to the cartilnge of the 
seventh. Tlie eleventh nnd twelfth aro floating nbe, and are 
only attached to the vertebree. 

It may be stated in general terms that inspiration is effect- 
ed by descent of the diaphr^m and elevation of the riba; 
and expiration by elevation of the diaphragm and descent 
of the ribs. 

Arising sever.dly from the lower border of each rib, and 



S€b 



B^PIRATIOa^. 



nttacLed to tlio npper boi'dcr of the rib below, are the eleven 
exteruEil jutercosUU muscles, the fibres of wliieli have an ob- 
lique ilirecticm frojii above cloMiiward and t'orwflrd. Attncbt'd 
to tlie inner borders of the ribs are the internal intercostal s, 
which have a direction ffom above dovk'Qwani and buckward, 
at right angles to the fibres of the external iutercostals. There 
are also a number of Tmiseles attAclied to the thorax and spine, 
thorax slid head, upper part of humerus, etc,, which are 
capable of elevating either the entire thest or the ril>9. 
These must aet as Jiiusule« af inepiration when the attach^ 
inenta to tho thorax become the uiovablB points. Some of 
them are called into action during ordluarj respiration; 
others act as aiisiliiiries when respiration ia a little exagger- 
ated, as after eserciic, and are called ordinanj aajrlliai'tea ; 
while others, width ordinarily have a diti'ei-ent functiun, 
are only brought into play when respiration is excessivelj- 
difficult, and are called extraordinary mixilkirie^. 

The folluwiug are the principal musclw concerned in In- 
epiration i 



Muscles of Impiration. 

Ordinary lieapirathn. 

jntwld Attaehmtias. 

Dlap]irftgm .Oireuftofeftiioc of lower bordet of thor&x. 

Scaleniu uiUcud Tr«lu<Ten>e prDceasca of tliirct, fciuiiii, 

finh, and sixth cervical Terwlirw 

tobercle of firiil rib, 
Scalenia medius , . , , TranHversc procuesa* wf sk lowei ccnri- 

C4l vertebnt upper surface of firrt 

nb. 
Scalanus poalicuB., Trausvcree praocesai of Icirer two or 

tliree cwrvi^^l iert«br» vut^r but- 

fnce of Araond rib, 

Extem^ Intercoatolfl .Outer Imrdcrs or tho riba. 

SteroAl portioD of iiLtcranl intereostalfl.. Bonders of Ibe coslitl ciiTlilu;;cs. 

Twi*Lv«> leTstOTM costMiiin Tnuurt.'rM! proce8^>es of dorsal ?ertebni 

ribs, bi'-lH-ecQ tbe tulwrclis And 



AonoH Q7 -rs£ diafheaqm. 



360 



Ordinars AvnUaritt. 

Muaete, AttneAntaU. 

femtiuPoBUciu Suiwrior. LtgnmiFntiim nuchal ppLnons pmccflan 

oi itil ceniral Atid uppor two or tbtM 
doTsal icrt^br^s^^uppcr borders of 
second, third, rourtb, niid 6flh rib« 
ju^t hcrouil llic ui-'lcM, 

6t«rao-ino8tolijeuj Upper part of sternum— —in aitoid pr» 

vem of t«mponl bon'O, 

^etraorJinary Aaxiliarin. 

Leirsiar Jlcgn]! ScApiiUe., , , .Tronsrenc procesBca of uppor three ff 

four wnical Twtebrw posterior 

bordurof^aperior iLti;!li.' of the scofiuU. 

Tnpcziiu (superior portlua) .Ligamieatiim nuchm and aerraith cervical 

Tcrtebra Ihe uppier bortHar of tUe 

spibQ or the ficajiiLli. 

PeotarallsHiaOr.. , ...4ai, ........ ^. .Comtcoid pmoes^ of Bcnpu]«i^^-aiit«rinr 

■iirface and upper mgrj^ni of thirii, 
fiiurtb, and fifth ribs npiir the cnrtilnges, 

Pectorvllg MiqOF (inferior portioa) .Biiiiiitiil groove of lumicruA^^-cuGtal 

uucn, 

S«mCa3 Hn^tia Inner marEUi of pnsterior bordsr ofuap- 

ulu exwnial HiiriaH.^ aad upper bor- 

(Sor of upper eight riba. 

Action of th. Duipkragm. — The deaerijitive and general 
anatomy of tbe diapliragui glvi^a a pretty I'orrect idea of its 
funetiong in respiration. It arises, anteriorly, from the inner 
surface itt" t-he ejiaiJovra cartilage, laterally, from the inner 
enrfnce of the lower boriiorB of ibe costal eartihiges and the 
BIX or seven inferior ribs, passes over the qaadrattis luraborum 
by the external arcuate ligament, and the psoas magnus by 
the internal arcuate ligament, and has two tendinous slips of 
origin, called crune of the diaphragm, from the bodiea of the 
second, third, and fourth lumbar verJebne and the interverte- 
bral cartilages on the right side, and the second and third lum- 
bar vertebne and tbe intervertebral cartilages on tlie lett side. 
From this origin, which extends around the lower clreiiinfer^ 



370 



EESPffiATION. 



ence of the tKorax, it monuts up into tliu cavity of tlie cbe«t, 
Ibrmiag a vaulteJ arch ur Joiiie, willi ita concavity toward 
tlie abdotitcn ntid its convexity toward tlie lungs. In the cen- 
tral portion iliere is a lendoD of considerable aizo, and shaped 
something like tbe club on a playing cnnl, "witli middle, 
right, and left leaflcta. The remainder of the organ is com- 
piled of radiating fibres of tbe striped or voluntary ratiscnlar 
tJaauc. The tesophagus, aorta, and inferior vena cava pa^ 
through the diaphragm from the thoracic to the abdominal 
cavity, hj three openioga. 

The opeoiDg for the oesophagus is surrounded by mtiscuUr 
fibres, by which it la partially elosed ■wheu the diaphragm 
contracts ia in&piratioTi, as the fibres simply eurruund the 
tnbe, and none are attached to it. 

The orifice for the aorta is bounded by the bone and 
aponeurosis posteriorly, and in front by a fibruns band, to 
which the muscular fibres are attached ; so that their con- 
traoiion has rather a tendency to. incri^ase, than lUmEuIsh, the 
caliber of the veaseL 

Tbe orifice for the vena cava h surrounded entirely by 
tendinous structure, and contraction uf the diaphragm, though 
it might render the foi-m of the orifice more nearly circular, 
can have no ett'ect upon Ita caliber. 

The action of the diaphragm can be easily stndied in the 
inferior animals by "rivisections. If the abdomen of a c&t, 
which, from the conformation of the parts, ie well adapted to 
thjsexjjcriiuentjbo largely openerl, wc can ohserv-e tbedeacont 
of the tendiuou£ portion, and tbe cuDtraction of the mugculux 
fibres, The action of this mn^lc may be rendered intire 
apparent hy compressing the walls of the cheat with the hands, 
BO as to interfere eomewbat with the movements of tbe rilis. 
In ordinary r^pirafion, the descent of the diaphragm and 
its approximation to a plane h the chief phenomenon ob- 
eerved; but as thery h r slight reei&tatite to tbe deprdfe- 
eion of the central tendon, it is probable that there i& also a 
slight elevation of the iuierior riU, the diaphragm aasialing, 



ACTION 07 TB& DlAPfLBAOU. 



an 



la a limited degree it is true, the action of tlie external 
iutcrcosluls. 

The phenomena referable to the abdomen, which coincide 
■with ttie descent of the iliujiliragiaj can easily \tG observed 
iu the human suliject. Ai^ the diaphragm is depressed, 
it neceesarilj pnshes the viscera before it, and inspiration 
13 tlieret'ore flceompanied hv protrusion of tlie abdomeD. 
Tliis may be rendered very marked by a forced or deep in- 
spiration. 

The action of the diaplirapn may bo illustrated bya very 
simple yet strikiii}^ experiment. In an animal just killetl, 
atfer ojiening the abdomen, if we lake hold of the stractnree 
which are attaclied to the central tendon, and make traction, 
we imitate, in a rough way, the movemeuts of tlie dinphrngui 
in respiration, and the air will pass into the Inngs, sotnetimes 
with a dietinctly-audible sound. 

The effectfl of the action of the diaphragm upon the size 
of its oriticea are chiedy liiuiteJ to the cesophageal opening. 
The anatomy of the parts ia such tliat contraction of the 
muscular fibres has a tendency to close this oritice. Wlien 
weoonie to treat of the digestive system, we shall see that tliis 
is auxiliary to the action of the muscular walls of the ocao- 
phagns itself, by whicli the cardiac opening of the stntiiach 
is regularly- cloeetl daring inspiration. This may become 
important wlien the stomach 'n much distended; tor descent 
of the dia]tliragni compreesea all the abdominal oi'gans, and 
might otherwise cause regurgitation of a portion of its con- 
tents. 

The contractions of the difiphragm are aoimated almost 
exelnsivel}', if not exclusively, hy t!ie phrenic nerve; a nerve 
which, having the office of supplying the most important 
respiratory muscle, derives ita filaments from a number of 
Boorces, It arises from the third and fourth ct-Tvical nerves, 
receiving a branch &om the fifth, and eometimea from the 
sixth; it pusses thronj^h the chest, peuetratoe the diiqihn^ni, 
and is distributed to ita under Burlace, This neiTe was the 



372 



BEBPIBATION^. 



subject of DTtinprous exporimenta bj the earlier phvsiologista, 
who were greatly interested in tUe minutia) uf tbe nctioii of 
the diaphragm, and otber ransclefl, in respiration. Its g»l- 
vaiuzatioii produces eonrukive c-oti tractions of the diaphragnit 
and its Motiun paralyzes tlje nmscJe ahnc^t eonijdetelj. It 
was noticed by Lower, that after eection of both phrenic 
nerves the movements of the abdomen were revei-sed, unil it 
became retrnrted in inspiration.' Tliia is explained and illus- 
trated by voluntary Biispension of the action of the diaphragm, 
and esa^geratiou of the costal morementa. As the ribe are 
raiaod, the ntmoapberic pressure causes the diaphragm to 
mount tip into the cavity of the thorax, and of courae the 
abdoiuinal organs follow. 

Front the great increase in the capacity of the chest pro- 
duced by the action of the diaphragm, and its constant and 
universal action in respiration, it innst be regarded as by far 
the most important and efficient of the muscles of inspiration, 

Hiccougli, sobbing, laughing, and crying are prodacod 
mainly by the action of llie diaphragm, partit-uirtrly hie- 
congh and sobbing, whieh are ptoducwj by Bpasmodic uon- 
trRL'^tioiis of this muscle, generally beyond tlie control of the 
will. 

Aeiiojiof the Mu^l^swMeh devaU th« li^. — Soalen« 
Musdei. — Tn ordinary r^piration, the ribs and the entire 
chest are elevated hy the combined action of a number of 
inu£cle». The three scalene muscles are attached to the cervi- 
cal vertebriE and the first and secoml ribs. These muscles, 
which act pai'ticularly upon the first rib, must elevate witli 
it, in inspEratioUj the rest of the thorax. The articulation of 
the iirat rib with the veitebral column is very movable, but 
it is joined to the steiiiuni by a very short cartilage, which 
allows of very little movement, so that its elevation necessa- 
rily carries i\*itb it the atemntn. This movement increase 
both the traosverse and autero-po&tenor diameters of the 

- ' BJcRASD, Coan df Phyioloi^, Paris, 1861, torn* Eli, p. 1211, 



ACTION OF TOE SCALENI. 



373 



tliorox. frym tlic mode of articulation aod direction of tLe 
ribfl, wbicli are soiiiewliat rcitatei.! as wuU m itadered moro 
horizoiital. 

Perhaps there is no set of muscnlar actions to wlilcli a» 
much ob&crvfltion and epecnlaticm have been devoted aa those 
concerned in rosjuration ; and tlie actions of the mnselea 
which are attached to tlie thorax are ao complex and difficult 
of observation, that the views of phyeiologUts conce-rning 
them are still soniewliat conflicting. "While some adopt Ihe 
(rptnion of Ilaller/ that the iirst rib is almost tised aad im- 
movable, otiiers C'juteiid, as did Mogeudie, that it i& tlie 
most movable of all.' With regard to this point thei"e can 
now, it seetiiB, be no doubt. By putting the thnrah and fiii- 
ger on either aide of the neck over the sealeni, we can dts- 
tinctly feel these nmscles contract with every tolerably deep 
inspiralioti (a moTemeut which Majjeudie proposed to eaU 
the reji](iratory pulse, Im.'. di.) ; and it ib farther evident 
that though in tho male, iu ordinary rt-spiralion, the sternum 
is aloiost motionless^ in the female, and in the male in deep 
iiispirationB, the eternum Ib considerably elevated and pro- 
jected, ])artit;ularly at ita lower part. This latter movement 
increases the autero-posterior diameter of the thorax, and can 
be measured with an appropriate instrument. The elevatiori 
of the Btemum is necessitated by its close and almost iui" 
movablu coniieetion, tlirougli its short cartilage^ with the 
first rib. 

The action of the Bcaleni, wUde it is inconsiderably in 
ordiuary respiration in the male, in all cases renders the first 
rib practically a fixed point, li-oin which those intercostnl 
umsctes which rai^ the ribs can act. 



Inter>:o9t'xl Muschn. — Concerning the mechanism of the 
actiun of these muscles, there is great difl'erencc of opiuiou 
aiiKjng phyeiologltts ; bo much, indeed, tliat the author of & 

' EUmetiia Fk^otofjia, L4TU»niMB,lT81, Wmm liL, p. 23. 
' fretit £iiinentaiK de PkfftMiffia, tome IL, p. 31?. 



374 



EESPTBATTOIf. 



late elaborate work aihnits tlint tlie question 3a atill left in 
coniMerable nnceitainty.' The most elaborate researches on 
this poiut are those of Beau and Mai^eiat (^ArcAtves Oenerale* 
lie Mvdeeine^ 1843), and Sibson {Philmu/i'hical TrajiMtctionSj 
184C). The latter eeem to settle tlie qucetion of the mode of 
action of the iuterc&stftls, and exjilain stitiBfactorny certain 
poiots whifh even now are not generally' ajipreciated.' 

Let us firet note the changes which lake ]»lai.-e in the 
direction of the riba, and their relation to each other, in 
inspiration, before considering the way in which these move- 
ments are pr(>dat:ed. 

In the dorsal region, the spinnl colutUD forpie an arch 
with its concavity toward the chest, and tie ribs increase in 
length progressively, from above downirard, to the deepest 
portion ui' the areh, where they are longest, and then IiecimiC 
progressively shorter. "^ During inspiration the ribs approach 
to or recede from each other according to the part of the arch 
with which they articulate ; the foiii' superior ribs a]>proftch 
each other ant^jriorly and reeeda from each other po9terii:>rly ; 
the fourth and fiftli ribe, and the inleriuediate set (eixth, 
Beventh, and eighth), move further apart to a moderate, the 
diaphragmatic set (four inferior), to agreat extent. The Dp|>er 
edge of each of these ribs glides toward the verlebne in rela- 
tion to the lower edge of tlio rib above, with the exception of 
the lowest rib, which is stationary." ' 

These movements^ accurately and admirably deserfbod 
by Sibsod, and illustrated by drawings of the chest, empty. 



' LoHorr, TraiU it Phj^ti/ilQ^e, Pnti", I8d8, tome L, p. 7-1I, ft i^. 

*KbBOB'a kiticle Es the most ct>m])letc aver pabBfihed upon tlic mechanLmi oT 
r«tiinilion. Tlic ocLlon or Ib^c rcpiralory musdw waa obaenrcd in liTUWliona, 
■nd (he mechaabtD by which tho ci{>acit;r of tbi^ thorajt i« modi^fid U iUusUmtLtl 
In tb« moat iugeniaug nLitnncr bj niccliuaiciil CotittivoiiCd, feprcscDting the p<>fii- 
tion, olcr., dT tlie ribs, and theiir movguienLt. By dilaling the cheel aIW ilcath, 
■leo, hu kIlows llic cliBHf^ which tafct-a plnee in the direrdon of tlw riib« uid tbe 
ci>D9C(iiic:iit i^hoTicumg of certain mi is clef, vhich, lie kkpuki-b, jutuX url ■« mutcliw 
of inspiration, & Jikct which he hu taksa care to verify by vitiantiooL 
* giBSOK, op. at., p. &29. 



INTEEC06TAL MCSCLES. 




Anterior B«glon of the Thotax. 
Inaplntloii, Esplntlim. 



■*r»»*wiriai, iBtplratlun. 

rta. la. 





txflnaon. 



InsplntloB. 



376 



SEfifI&A.T10N. 



as ill esplratiiin, nnd distenJed with air, increase tlie antero 
postL'riur and transvei-bc dJametei-a of tlie tlioras. As tlie 
riba ai"e elevated and become more nearly horizoutal, tbey 
must pasli forward the lower portion of the sternum. Their 
configuration and mode of articulation witli the vertebne are 
fiucbjthat tliej cannot be elevated without underguiag a con- 
Biderable rotjition, by which the concavity looking directly 
tow^ard the lungs is increa&ed, and witli it tlie lateral diameter 
of tlie chest. All the intercostal spaces posteriori j are widen- 
ed in ins{>irution. 

These jioints are clearly illustrated in the accompanying 
diagrams.' 

The ribs are elevated by the action of the external inter- 
costals, the fiterual portion of the internal ii:tercostals, and 
the levatortfs costaruia. 

The e-ttemal intercoatals are situated between the riba 
only, and are wanting in the region of the coBtat cfirtilngce. 
As the vertebral extrcmitiea of the riba are the pi%'ots on 
which these levers move, and the eternal estremiljes aro 
mi>valde, the direction of the fibres of the intercostflfs, Irotn 
above downward and forward, rendere elevation of the ribs 
a neceseily of their contraction. ; if it can be assumed that the 
fii'st rib is fixed, or at least does not move downwai'd. The 
Bcalene muscles elevate the iirst rib in ordinary inspiration ; 
and iu deep inspiration, this takes place to such an extent 48 
to palpably carry with it the Bteriium and the lower ribs. 
Theoretically, then, the external intcrcoatala can do nothing 
but render the riba more iieai'ly horizoutal. The aetion of 
these muscles has, however, been the eubjeet of consideniblu 
controversy, on theoretical grounds. AVe shall discuss the 
que&tion chiefly from an expenmeutal point of view. 

It' the external intereostalB he exposed in a living animal, 
the dog for example, iu which tlie costal type of respiration 
is very marked, cloee obsen"atiou cannot fail to convince any 
one that these musctes enter into action, in inspiration. Thia 

' ElBSOH, lo<. tit 



TSTEOCOeiAl. UD&CIrES'. 



37T 



fact has been observeJ by Sibsoii and niauy other phjsiolfr 
gists. Il" attentltm be nnw ilirctted to tbe steraal portion of 
theintenial interco^taJs, situated between tbe costal cai'tilftges, 
their tilires liaviug a direction from above duMiiwai-d aud 
backwards, it is equally evident that they enter into action 
with inspiration. By artificially influting the luuga after 
death, Sibson confirmed these observations, and ebowed that 
when tbe lunga are tilled with air, tbe fibres of these miisclea 
are shorleiieil. lu iuspiratlon the ribs are all separated pos- 
teriorly ; but lateridly and anteriorly, some are separate (all 
T>elow the fourth), and some are approxfmated (idl ^buve ihe 
lutirth). Tl«iis all the lutt'Tapaoea, excepting the anterior por- 
tiuD ot' the upper thi'ee, are widened in inepiratiou. iSib:ian 
ha^ bliowii by inflation of ihe cheat, that though tbe riba are 
separated from caeh other, tbe aiijicbmentB of the intercostak 
are approximated. Tbe ribs, from an excessively oblique 
positiou, are rendered nearly horizontal ; tmd consequently 
the iiiforior attachments oi' the iiilercostals are brought nearer 
the epiual colutun, while the stiperlor altachnients on the 
upper borderfi of the ribs are slightly removed from it. Thus 
these muscles are shorteaeii. If, by separating and elevating 
the ribi5, the uiu&cles are shortened, shortening of (he muscles 
will elevate and aeparate the ribe. In the three superior 
iutct^paces, the constant direction of the ribs is nearly hori- 
zontal, and the couree of the intercostal fibres is not as oblique 
as in tbcHsesituftted between the lower ribs. These spaces are 
uarrowed in inspirntion. Tlie muscles between the costal 
cartilages have a direction opposite to that of tbe external 
intercottalis i^tid act upon the ribe from tlie Btemnm, as tbe 
others do from the spina] colninn. The euperior interspace 
\s narrowed, and the remainder are widened, in insjjiration. 

The probable explanation of the great difTerencc of opin- 
ion with regard to the action of the hitercostalR. is tbe diffi- 
culty of comprehending, at the first blush, that the contrac- 
tion of muscles sittiated between, the rtbd can separate them 
&om each other; a phenomenon which is easily understood 



3T3 



OEBPlBATIOa'. 



after a careful consideration of tlie relative position of tlie 
parts. 

Leeatorea CostaT^m. — The action of these raaeclee cannot 
be uiiataken. They have iinnrnvable points of origin, the 
tran&verse proeeasee of twelve vertebnc tram the la&t cervical 
to tlie eleventh dorsal., and, sprending out like a fan, are at- 
tached to tlie upper ed^^ea of the rilw between the tubercles 
and tlie angles. Jn inBpIration they contract and assist in the 
elevation of the ribs. They are more developed in man than 
in the inferior animala. 



AtmilMry Muicle$ of Inspiratton, — The muscles which 
Lave just been crrasidered are competent to increase the ce, 
pacitj of the thorax snffieieutlj in ordinary reepiratJon ; there 
are certain, muecles, however, wliich are attached to the ches* 
and tlie upper part of the spiriid cflluran, or U])per extremities, 
■which may act in inspiration, though ordinarily the chest ib 
the fixed point,, and they move the head, neck, or ajma. 
These muscles are broii<;lit into action when the movements 
of respiration are exaggerated, When thig esag|reratioji i& 
but slight and physiological, as alter exercise, certain of them 
(ordinaiy auxiliaries) act for « time, nnti! the tranquillity of 
the njovoinents is reBtored. But when there is obstruction 
in the respiratory passages, or when respiration is exccdflively 
difficult from any cause, threatening sutTocatiun, all the 
inuselos which can by any possibility raise the chest are 
brought into action. The principal ones are put down in the 
table und<?r the head of e^itraordinary nnxiliaries. Most of 
these muscles can voluntarily be brought into play to rai&e 
the chestj and the mechanism of their action can in this way 
be demonstrated. 

Serratus Posticus Superior. — TbiB muiicle arises from the 
ligamentum nuehie, the spinous proceefies of the last cervical 
and upper two or three doreal vertebne, its iibm pasMUg 



ACXILIARV 



tajBPmATTON. 



379 



obliqnely downwavt] and ontward. to be attached to the 
upper liorders of the second, third, loTirth, and lifth ribs just 
beyond their angles- By revereiug ha action, as we have i«- 
Tcrscd the deaeripfion of ita origin and inaertionB. it is capable 
of incrciiBiiig tlie cKjiacii-y of the thoiax, Sibsoti hfta seon 
this muscle contract in i[jsp]ratiynj in the dog and the ass.' 

Stemo-iiiastmdexts. — That portion of the muscle which is 
attached to tlie ma&toid proceps of tlie temporal bone and the 
Btemmn, when the bend is tixed, is cajmbJe of acting as a 
muscle of inspiration. It does not aet in ordinary respira- 
tion, bnt its eontractions can bci readily ob&erved whenoTer 
respiration ia }inrried or exaggerated. 

The following mnsclea, as a rule, only act aa muscles of 
inspiration when respiiation is exceedingly difficult or la- 
Iwred. In certain cases of capillfiry broneliitis, tor example, 
the anxious espression o^ the countenance betraya the sense 
of impending suffix-ation ; the head is tlirown boL-k and fixed, 
the sbouldera are braced, and every available muscle is 
bronglit intit action to raise the walls of the thorax.^ 

Levator AnffuH ScapnlcB CMid Superior Portioti of i/ie 
Trt/j'f^iti^. — Movements of the scapula have oiten lieen ob- 
served ill very labored respiration. Its elevation during in- 
Bpirntioii is chiefly efiecCed by the levator anguli scapulga 
and the upper portion of the trapezius. The ftirmer aj-iaes 
irom the iratisverse processes of the upper three or four cer- 
vical vertebnt^, and is inserted into the poaterior border of 
the geapula belotv the angSe. It k a thick ^at mu&clc, and 
wbeu the neck ia the fixed point, aasista la the elevation of 
the thorax by raising the scapula. The trapezius ia a broad 
flat umscle arisiDg from the occipital protuberance, part of 
the superior curved fine of the occipital bone, the ligaoientum 

Op, eit, p. 621. 
* UDd«r tbdM clrL^umsiAiiccs, some itiuBcIes nhich we hnvr^ net thouglit il iie- 
oeuciy to euumcraie may set Uiditcctly as mimclea ol la&^itAiiaa. 



330 



UESPrBATlOJr. 



mic-liip, find tbe spiiinns jirows-^ps of the last cervi.'Hl niiil all 
the ciorsftl Tcrtebne, to be inserted iuto the upper Ix^rdcr of 
the spiue of the scapula. Acting from its attachnieiita to the 
Occiput, the ligaiiieDtuni iiucbs?, tlte last iiervical vertebra, 
and perhai>s one or two of llie dorsal rertubne, tliie lUUBcle 
may elevate the Bcapula tmd asdiat in inspiration. 

Pectoralis Mhor and I'nfeHiir Portion qftAe Pectoralui 
3ffTj&r.-^These mnsclea act together to raise the n'hs in diffi- 
cult re&piration. Tbe pcctoralig minor ia the more e^cienC 
Traciiig^ it from its attacbment to the coracold process of the 
scapula, its fibres pa&s downward aad forward to beattacbetl 
by throe imli^'itations to the externa] surface and up[jer mar- 
gins of tbe third, fourth, and fifth ribs, jiiat posterior to tho 
cartilages. With tiie corficoid process as the fixed point, this 
muscle is capable of iiowerfiilly fissisting' in the elevjitioii of 
the ribs. That portion of the pectoralis major ^vhifih is at- 
tached to the lower part of tbe Btemum and costal cailili^es 
18 capable of acting from its insertion into tbe bicipital 
groove of the humerus, when the shonlders are iixed, in con- 
cert with tbe pectoraba minor. In great dyspnoea, it is fre- 
quently observei] that the shouldera are braced, the pectoraU 
acting moat vigorously to raise the walls of the chest. 

Serratus Magnus, — Thia is a broad tliin muscle covering a 
great portion of tbe lateral walla of the thorax^ Attached ix* tbe 
inner margin of the posterior bur<ler of the scapula, its fibres 
pass furward and downivard, and are attached to tbe ester- 
]ud surface and upper borders of tbe eight superior ribs. 
Acting from the scapula, this muacle ia capable of assisting 
the pectorals in rnisinji; llie ribs, and becomes a powerful aux- 
iliary iu dltlicult inspiration. 

"Vfe have thus considered tbe functions of the principal 
inspiratory muscles, M-ithout taking up those which have an 
inaij^itiirant or undetermined action. In many animals the 
n area are considerably distended in inspiration; luid in tbo 



AUXnJABT MUSCLES OF ISSPIKATIOX. 3S1 

horse, which does not respire bj the month, these movements 
are as essential to life as are the respiratory muvcments of the 
larjnx. In man, as a rule, the narca undergo no movement 
unless respiration be somewhat exa^eratod. In very diffi- 
cult respiration the niouth is opened at ca(;Ii inspiratory act. 
We have not thought it necessarj' to treat of the action of 
those muticles which serve to lix the head, neck, or Bhouldcra 
in dyspnoea. 

The division into muscles of ordinary inspiration, ordi- 
nary auxiliaries, and extraordinary auxiliaries, must not be 
taken as absolute. In the male, in ordinary respiration, the 
diaphragm, intercostals, and levatores costarum are the great 
inapiratoiy muscles, and the action of the scaleni, with the 
conseqnent elevation of the etemum, is comraouly very slight, 
or perhaps wanting. In the female, the movements of the 
npper parts of the chest are very marked, and the scaleni, the 
Berratus posticus superior, and sometimes the stemo-mastoid, 
are brought into action in ordinary respiration. In the vari- 
ous types of respiration, the action of the muscles engaged in 
ordinary respiration necessarily presents considerable varia- 
tions. 



26 






CHAPTER XL 



uovmiEsn of ££pmA.Tioy, 

Idfluenie of tlic eloeticitf of the pulmonBrj alnictuR and walls at tho clits^— 
MusLilcaof eipirstion— Intcm&l intorco.ttiil^^InrnicoiU.le^^Trtiili^iilju-ifr ste*^ 
ni — AcUou of the nthdorainRl muBcleB in eTpiration — Types of ^(^spi^lli<>II^ 
Abdorainal type— Itiferior cosUil typi — Supariot cofLal t_Tpe — F'requcijc* of ihs 
FC9;]iiralQry niovenicDl^ — BcllkCvoss of in^piratiun AHiI >i!xpirB.tion locaoholhcr— 
The retipimlory aoiiniJa — Cougljing — ^ncGziag — Sigljing — Y awnings t-auyh- 
ing — Sobbing — EiccDusb — CEkpKcity of Ili>e Iimge aati the (|uanl1ty of m 
changed in therespipaKiryauW — l{eeidual>ir — Beafireaiir — Tidal, oc bre«lhtEii: 
air — CorapLemGiLtal &ir — Excrctne brMtltIng oupuit}' — K^^tiana in Tolume of 
the expired to tbc inspicod aiir — Ditfuftion of air ia tbc luogH. 



Tee sir is expelled fifoni the lungs, in ordinary expiration, 
by a simple aud comparatively passive process. The lun^ 
contain n great number of elastic fibres Burronndin^ tho air- 
cells and the smallest raniification& of the bronchial tiibea, 
which give them great elasticity. We caai form an idea of 
the extent of elasticity of theae organs, hv simply removing 
them from the cheat, when they collapse and become many 
times smaller than the cavity which they before completely 
tilledr The thoracic walls are also very elastic, particalarly 
in young persons. After tho nmscles which increase tlie 
capacity of the thorax ceMe tbelf action, the elasticity of the 
costal cartilages and the tonicity of muscles which have been 
]mt on the stretch, will restore the chest to ivhat we may call 
ita paeaive dimenaious. This elasticity is likewise capable of 
acting as an inspiratoij force when the chest haa been com- 



EXPrnATIOS", 



38A 



pressed in any wnr. There are also certain mu^desj tlie 
action of which iv, to draw the ribs doTniward, and which, ia 
tr«nf|iui respiratitiTi, are antagoni&tic to tliose which elevate 
the nhs. Aside IroTii tlii*, many operatioos, such as eiwak- 
ing, blowing;, singing, etc., require powerful^ prolonged, or 
complicated acts of expifAtiotj, in whicli numeronB ninsclea 
are brought into play. 

Expiratiun may be considered as depeading upon two 
causes: 

1. Tlie passive influence of the elasticity of the lungs and 
the thoracic walk, 

2. The action of certain muscles, whicli either dimiuieh 
the transverse and antero-pnsterior diameters of the cheat by 
deprussiiig the ribs and sternuiu, or tht* vertical diameter b}' 
pressing up the abdominal vieeera behind the diaphragm. 



Tfifiiience of Uie Elu-ni'teihj of the Pulmonary StT^icture 
awl Walla nf tli^ Chest, — It ii^ easy to understand the in- 
ftnenoe of the elasticity of the -[lulmonary structure in expi- 
ration. From the collapse of the lungs when openingis are 
made in the chc&t, it is seen that even after the mo$t complete 
explr&tioti, those organs have a tendency to expel part of their 
gaseous contents, which cannot be fully satisfied until the 
cheat is opened. Tliey remain partlaHy distended, from the 
impoBaibility of collapse of the thoracic walls beyond a certain 
point; and by virtue of their elasticity, they e\ert a auction 
tbrce upon the floor of the thorax, the dJaphragm, causing it 
to form a vaulted nrcb or dome above tlic level of the lower 
circunifereuce of the cheat. When the lungs are collapsed, 
the diaphragm hangs loo&ely between the abdominal and 
thoracic cavities. In inspiration and in espiration, thenj tho 
relations between the luugs and diaphragm are reversed. In 
inspiration, the descending diaphragm exerts a suction force 
on the lungs, drawing the ni down ; in es].uration, the elastic 
lungs exert a suction fc>rce upon the diaphragm drawing it 
Up. ThiB antagonism is one of the caus^ of the great power 



BESPm&TION. 



ut'tbe dtapTiragni as an inspiratory innecle. Ciireon,!!! 1S20,' 
was ilie first to uote the relatmu of the elasticity of tin? lung;s 
to tho expulsion of air. Introducing a U tube partly filler! 
with water into the trachea of an atiimat just killed, atid 
securing it by a ligature, tlais obeerrer noted a considerable 
pressuix; on opening the chest ; equal Id the calf, sheep, or 
dog to a column of water of from 13 to IS inches, and in the 
cat or rabbit, from fJ to 10 inchea/ 

The claeticity of the lungs operates chiefly upon the dia- 
phragm in reducing the capacity of tlie cbent ; fur the 'walls 
of the thorax, bj' virtue of their own elasticity, have a reac- 
tion Tvhieli sueceeda the ruovements produced by the luspi- 
ratorj^ muscles. A pimple experiment, which we have often, 
performed in public demon et rations, illustratea the chief ex- 
piratory influence of the elasticity of tho lungs. If, in an 
aniraal just killed, we open the abdomen, seize hold of tho 
vena cava as it pjisaea through the diaphragm, and make 
traction, we imitate the action of this muscle snfficientlj to 
produce at times an audible inspiration ; on loosing onr hold, 
we have expiration, as it is in a. measure accomplished in 
natural respiration, bj vh-tne of the resiliency of the Itings, 
carrying the diaphragm up into the thorax. 

Though tins i& the main action of the luuga thcmselvcB 
in expiration, their relationa to the walls of the (borax are 
important, By virtue of their elasticity, they assist the pas- 
sive coUajiae of the chefit. When they lose thia propertj" to 
any considerable extent, aa in vesicular emphy&cma, they 
offer a notable resistance to the contraction of the tlioraic ; w 
ninch, indeed, that in old eases of this disease the movetnents 
ate much reetricteJ, and the che^t presents a characteristiu 

' f^Uiuopklail 7)ran»arll<yn», 1820, 
, ^ If, idW noling the clH;<iatimi in Hie Uqutd due to the uliiBTicity of ibe |i4Bgii, 
Lheae oigiuia be alininlaioci by [ucaiis of b curKOt of gal»4i!iism, the licLoiil will 
gi-adiinlly riice, in t)l:)ei.)ii!Lice to U)u coDlnctloiu o-f ihe maociUiir cleini'Ute of cho 
brondiJaJ tubca. This bI-dw coDtTnctian, cbankcicii£tii>n nf tbc non-jirtaicd muwu- 
lar librf^^ doca not intervene in the phyHeologieol phenamFniL of expinidan, but 
Lhc tieticiD of tbcsc fibres is Impflttnnl in cerbiin co&cs of diiease. 



KZPXE&TI037, 885 

Tomided and distended appearance. In &ome of these casea 
the elasticity ol" flie lungs id so far lust, that when the cliest 
15 oponed atler denth, they are actually protruded, instead of 
coUapaed.' 

Litite more need be said concerning the passive more- 
ments of tlie thoracic walls. When the action of the inspi- 
ratory musclea ceases, the ribe I'cgaiii their oblique direction, 
the iutereobtai spaces are narrowed, and the stormiru, if it 
have been elevated and drawn furwai-d, tails buck to its place 
hy the simple elasticity of the parts. 

Aftioii, of Musclea in Eu^piration.. — The following are the 
principal muacles coucserneii in expiration : 

Mvscles of Mtjfiraiion. 

Ordinarg hMpiration, 

ita»:U jtltatXmmlt. 

(>3Scou9porli<niol''lDli!rmil iTiU-rcoalftl?,, Jnnpr bordpts a!iht riha. 

Infra-costdlt*. liiner SurTateS of the riha, 

TrtatLgiiloHd StcmJ Euxirorui ciirlilagp, lower bord(>M of 

Bleraum, lower thrca or £bir cosWl 

eartil>\^-& canilngea of the eecmiii, 

ibsrd, fourtli, uiid fifLh ribs. 

* In old oa£C9 of cmphyscmn, the clitBt gvnerdl]' becomes iquii(I<k1 and dia- 
toide4, fireacnting consuinilj the apiieanuK^e whk'b it Ima in forced iuspkradan. 
Tltia » expIaiQcl iii lli-c Mlovtiiij; wa,r : EmplijsGtiu. is gcnerallj- prccLilcd anil 
accompanied hf a. dilBcultjr in respiratior, from eome cauae wliicli ta mor* of ksa 
ciitislaiit. This givtjs rise to frcqiicnt TioltDt movctnttiia of Ijk^i lira linn, when the 
Sunc^ EJid i^hfSt JitT dintebded to their Utmost t;apjitilj. In thb conditioD, eijil- 
iitlion is difficult, and tho ch<»t collapses but iiii[wrfectly. GniiLuultj-, iia Ibo pei^ 
iDHiimit dilalatioti of the tur-cclla gnins ground, the hiii^ lose their dastidtv, and 
ortl-r congidurable reBistance (o the collapse of the Ihoracio nall.i. Hut difflciilt 
li[-(!iitbLDg, uid CiOiiBcqiieiit vi^knt flcvittiuu of llie riiiK, bKOnrics mQic aoi more 
frcquciii ; Chc chcnt la conBt;iutly dLlatcJ, the luiigs fulloiviiig, of coiiraf, but nfa*^ 
tug to CDll.kpse in cxpiratLoa, until ihe cli&^t betoiiR'S ;icruiiiucDlly diElCQiied. In 
tbifl condition, Che lunga preas dctmn'ard, u well m laterally, and tlic moTcTneala 
of the dlftplin^ nre conslUGmblj rcatrict^d. 



386 BESPISAIION. 



AvxiliarUt. 

MutcU. AaackmanU. 

Ubliquufl Extemiu Eztenutl eurftce tnd iuferior borders of 

dgbt inferior ribs tbe aoterioi 

half of the KK&t of the ilenm, Pou- 
part'a ligvaent, lineft ftU». 

Ubliquus Intemns , Outer half of PouparfB ligament, ante- 
rior two-thirds of the crest of tho 

ileum, lumbar fiuda cartilages of 

four inferior ribs, lineal alb*, crest ol 
tiie pubis, pectineal Una 

TroosTersalis Outer third of Foupart's ligament, ante- 
rior two-thirdg of the crest of the 
ileum, lumbar vertebrae, inner sur- 
face of cartilages of riz inferior riba 

crest of the pubis, pectineal line, 

linea alba. 

Sacro-lumbalis Sacrum angles of the fax inferior 

ribs. 

Jntertujl Intercostala. — The internal intercoBtala have dif- 
ferent functions in diflferent parts of the thorax. Tliey are 
attached to the inner horders of the rihs and costal cartilages. 
Between the ribs they are co\ered by the external intercos- 
tals, but between the costal cartilages are simply covered 
by aponeurosis. Their direction is from above downward 
and backward, at right angles to the external intercostala. 
The liinction of that portion ot* the internal intercoetals situ- 
ated between the costal cartilages has already been noted. 
They assist the external intercostals in elevating the ribs in 
inspiration. Between the ribs these muscles are directly an- 
tagonistic to the external intercostals. They are more nearly 
at right angles to the ribs, particularly in that portion of the 
tliorax where the obliquity of the ribs is greatest. The ob- 
servations of Sibson have shown that they are elongated 
when the chest is distended, and shortened when the eheet is 
collapsed. This fact, taken in connection with experiments 
on living animals, shows that they are muscles of expiration. 
Tlieir contraction tends to depress the ribs, and conseqnentJy 



rSFHACOSTALES — ^TEIASGULAHS 6TEKSI. 3S7 

to diminish the capacity of the chest. If we hring an ani- 
mal, a dog for example, completely under tlie infliieuee of 
ether, expose the walls of the chest, dissect off the fascia from 
some of the estemal intercostols, then remove carefully a 
portion of one or two of these muscles so aa to expose the 
fibres of the internal intercostals, it is not difficult, on close 
examination, to observe the antagonism between the two sets 
of mnscles ; one being brought into action in inspiration and 
the other in expiration. 

Infracoetalee. — These muscles, situated at the posterior 
part of the thorax, are variable iu size and uumber. They 
are most common at the lower part of the chest. Their 
fibres arise from the inner surface of one rib to I* inserted 
into the inner surface of the first, second, or third rib below. 
The fibres follow the direction of the internal intercostals, 
and acting from their lower attachments, their contractions 
aaeist theee mosclcs in drawing down the ribs. 

Triangularis Stemi. — Tliere liaa never been any doubt 
concerning the expiratory function of the iriaugularis stemi. 
From its origin, the ensifonn cartilage, lower borders of the 
stemnm, and lower tliree or four costal cartilages, it acts 
npon the cartilages of the second, third, fourth, and fitlh ribs, 
to which it is attached, drawing them downward, and thus 
diminishing the capacity of the chest. 

The above-mentioned muscles are called into action in 
ordinary tranquil respiration, and their sole function is to 
diminish the capacity of the chest. In labored or difficult 
expiration, and in the acts of blowing, phonation, etc., other 
muscles, which are called auxiliaries, play a more or less 
importuit part. These muscles all enter into the formation 
of the walls of the abdomen, and their general action in 
ejqpiration is to press the abdominal vii^cera and diaiihra^m 
into the thorax, and dimiuijjh its vertical diameter. Their 
action is voluntary; and by an effort of the will it may be 



3S3 BESPIEATION. 

opposed more or less by the diapliragm, by which means the 
duration or intensity of the expiratory act is regulated. 
They are also attached to the ribs or costal cartilages, and 
while they press up the diaphragm, depress the ribs, and 
thus diminish the autero-posterior and transverse diameters 
of the eliest. lu this action they may be opposed by the 
voluntary action of the muscles which raise the ribs, also 
fur the purpose of regulating the character of the expiratory 
act. The importance of this kind of action in declamation, 
singing, blowing, etc., is evident; and the skill exhibited by 
vocalists and performers on wind instruments shows how 
delicately this may be regulated by practice. 

In labored respiration in disease, and in the hurried 
respiration after violent exercise, the auxiliary muscles of ex- 
piration, as well as of inspiration, are called into action to a 
considerable extent. 

Ohliquvs Extemvs. — This muscle, in connection with the 
obliquus intemus and transversalis, is efficient in forced or 
labored expiration, by pressing the abdominal viscera 
against the diaphragm. Its fibres run obliquely from above 
downward and forward. Acting from its attachments to 
the linea alba, crest of the ileum, and Poupart's ligament, by 
its attachment to the eight inferior ribs, it draws the ril« 
downward. 

Obliq^ius Internus. — This muscle also acts in forced expi- 
ration by compressing the abdominal viscera. The direction 
of its fibres is from below upward and forward. Acting 
from its attachments to the crest of the ileum, Poupart's lig- 
ament, and the lumbar fascia, by its attachments to the carti- 
lages of the four inferior ribs, it draws them downward. 
The direction of the fibres of this muscle is the same as that 
of the internal intercostals. By its actioa the ribs are drawn 
inward as well as downward. 

Transversalis. — The expiratory action of this muscle is 
mainly in compressing the abdominal viscera. 




TTPE8 OF KESPIRATION. 389 

Sacro-lvfnhalis. — Tliis muscle is situated at the posterior 
portion of the abdomen and tliorax. Its fibres pass from its 
origin at the aaenim, upward and a little outward, to be in- 
serted into the six inferior ribs at their angles. In expira- 
tion it draws the ribs downward, acting as an antagoiiiat to 
the lower levatorcB coatamm. 

There are some other muscles which may be brought into 
action in forced expiration, aseisting in the depression of the 
riba; snch as the aerratus posticus inferior, the superior Hhres 
of the serratus raognus, tlio inferior portion of the trapezius; 
bat their function is unimportant.' 

Type» of liespiration. — In the expansive movemeuta of 
the chest, though all the muscles which have been classed la 
wdinary inspiratory muscles are brought into action to a 
greater or less extent, the fact that certain sets may act in a 
more marked manner than otliers hits led pliysiologii^ts tu 
rect^ize different tyiHJS of respiration. Following Beau 
and Maissiat, three types are generally given in works on 
physiolt^ : * 

1. The Abdominal ttjpe. — In this, the action of the dia- 
jliragm, and the consequent movements of the abdomen, are 
most prominent. 

2. Ths Inferior Costal type. — In this, the action of the 
annscles which expand the lower pai't of the thorax, from 
'the seventh rib inclusive, is most promiiient. 

3. TKe Superior Costal type. — In this, the aetiuii of the 
moacles which dilate the tiiorax above the seventh rib, and 
'^hicb elevate the entire chest, is most prominent. 

' It Ib nnoertidn whether the Gtniight uiusl'Ii'j of the ubilomen arc ever con. 
^aened in expintion. From their situation, it might be dupita-ieJ tlmt thtiv woiilil 
^an lOtDe action in the more riolent pliciiomeua of ex^iratiun, sucl) as >meexiu^, 
^aoD^ing, cryiiig, etc; but Beau aud Moiiti^iai, wliu have iure^tt^atcil these queiv 
'ftiont ret7 carefully, slate tlmt in doga they liavo never seen theM roiisules act. 

I in the mott violent elTurts. {^Archicii Giairales, 4tli i>erii:i, vol. iii.) 

■ ItcA 



890 BE8PIEATI0N. 

The abdominal typo is most marked in cliildren under 
the ag;e of three years, irrespective of sex. In them, respirar 
b'on is carried on almost exclnsively by the diaphragm. 

At a variable period after birth, a difference in the tv^es 
of respiration in the sexes begins to show itself. In the male 
the abdominal, conjoined with the inferior costal type, is pre- 
dominant, and continues thus through life. Bi the female the 
inferior costal type is insignificant, and the superior costal 
type predominates. Observers differ in their statements of 
the period when this distinction in the sexes becomes appa- 
rent. Haller states that he observed a difference in children 
less than a year old. Beau and Maissiat state that after the 
age of thi-ee years the superior costal type b^nsto be marked 
in the female. Sibson states that no great difference is ob- 
servable before the age of ten or twelve years." Without 
discussing the nice question as to the exact age when this 
difference in the sexes first makes its appearance, it may be 
stated in general terras, that shortly before the age of pu- 
berty, in the female, the superior costal type becomes more 
marked, and soon predominates ; while in the male, respira- 
tion continues to be carried on mainly by the diaphragm and 
lower part of the chest. 

The cause of the excessive movements of the upper part 
of the chest in the female has been the subject of considerable 
discussion. It is e\ndent that it is not due to the mode of 
dress now so general in civilized countries, which confines the 
lower part of the chest, and would render movements of ex- 
pansion somewhiit difficult, for the same phenomenon is ob- 
Ber\''ed in young girls, and others who have never made use 
of such appliances. But there is evidently a physiol<^cal 
condition, the enlargement of the uterus in gestation, which 
at certain times would nearly arrest all respiratory move- 
ments, excepting those of the upper part of the chest. The 
peculiar mode of respiration in the female is a provision of 
If aturo against the mechanical dilliculties which would others 

' Lonorr, IVmU dt PAyno^ie, Paris, 1S68, tome l, p. tZI. 




PBEQCZNCT OF BESPIRATORY HOV£L^IE^'TS. 391 

wise follow the phyBiological enlai'gement of the uterus, [n 
pathology it is observed that, in cousequence of this peculiar^ 
itj, females are able to carry, without great inconTciiieuce, 
immense quantities of water in the abdominal cavity ; while 
a much smaller quantity, in the male, produces great distress 
irom difficulty of breatliing.' 

Frequency qf the Respiratory M&vcmenta. — In counting 
tiie respiratory acts, it is desirable that the subject be nucon- 
acioos of the observation, otherwise their normal character is 
apt to be disturbed. Of all who have written on this sulw 
ject, Hutchinson presents the most numerous and convincing 
collection of facts. This observer ascertained the number of 
reepinttory acts per minute, in the sitting posture, iu l,Si)7 
xnsJes. The results of his observations, with reference to fre- 
quency, are given in the following table:* 

B w pha U uM pw mlitate. Number cfeuti. 

fhimStolS 19 

16 239 

lY lUB 

IB 195 

19 74 

20 B61 

SI 129 

Sa 113 

SS 42 

M 243 

Mto40 67 

Though this table shows considerable variation in differ- 
®t iudiridaals, the groat majority (1,731) breatiied from six- 
*^*i to twenty-four times per minute. Xearly a third 

**Bathed twenty times per minute, a number which may \m 

**Gn aa the average. 

Jlo^flcatioiu of the tipca of respiration br discaao are frcqucntlv very 
^""^•d. In perttonlds, when movements of the diajiliragin would be productive 
^ "'^ CB wl Te pain, the Bbdominal type ro.iy be wholly suppresdciL In the early 
> ot Hute pleoiiiy, the affected »idc may become nearly or quite mutionlc^^ 
Cjirfy d i a of Anatomy and Phi/aiology, vol. ir., part il, p. Iu89. 



393 BESPIOATION. 

The relations of the respiratory acts to the pulse are quito 
constant in health. It has been shown by Hntchinson that 
the proportion in the great majority of instances is one re- 
spiratory act to every four pulsations of the heart. The sanie 
proportion generally obtains when the pulse is accelerated in 
disease, except when the pulmonary organs are involved. 

Age has au influence on the frequency of the respiratory 
acts, corresponding with what we have already noted with 
regard to the pulsations of the heart 

Quetelet gives the following as the results of observations 
on 300 males : 

44 respirations per minute soon after birth ; 

26, at the age of five years ; 

20, at the age of fifteen to twenty years ; 

19, at the age of twenty to twenty-five years ; 

16, about the thirtieth year ; 

18, from thirty to fifty years. 

The influence of sex is not marked in very young chil- 
dren. The same observer noted no difierence between males 
and females at birth ; but in young women the respirations 
are a little less frequent than in young men of the same 
age.' 

The various physiological conditions which have been 
noted as affecting the pulse have a corresponding influence 
on respiration. In sleep the number of respiratory acts is 
diminished about twenty per cent (Quetelet). Muscular ef- 
fort accelerates the respiration pari passu with the move- 
ments of the heart. 

Rdailons of Inspiration and Expiration to each other. — 
T/te RespircUory Sounds. — In ordinary respiration, inspira- 
tion is produced by the action of muscles, and expiration, in 
greatest part, by tlie passive reaction of the elastic walls of 
the thorax and tlio lungs. The inspiratory and expiratory 
acts do not immediately follow each other. Commencing 

' MujiE-EDTFARDS, LtfonM de PhyKoioffte, tome iL, pp. US, 488. 



BIXATIOKS OF IXSfllLATJON ASLI EXPIKATIOS, 393 

witli insjairntion, it i& roim(3 tliat tliU not mainraiDs about tlift 
siuiie JDtensity i'rom Its ctnumenceniicnt to its terminatioD ; 
there is then a very briof interval, v^hen expiration foUowa, 
wliicli Las ita maxJrimm of inteneity at the coraiuencement 
of t}ie act, and gradually dies away.' Between the aata of ex- 
pinitiou and insijirjition ia an interval, somewhat longer than 
that which occnrs after inB|iirat[on, 

The iluratJon of expiration ta generally soincTvliat greater 
than that of inspiration, tliongh they may he neai-ly, or in 
BOMiti instances quite, efjual. 

Afrt-r from tive to eight ordinary respiratory acta, one 
generally occurs which is rather more prut'uiiuil than the refit, 
and by which the air in the lungs is mure eliectually t:hauge<L 
The temporary arrest of the ac-ta of respiration in all violent 
mu3eiilar fcfforts, in straining, in parturition, ete,, is fatailiai* 
to all. 

Ordinarily respiration is not accompanied by any sound 
wliich can he heai-d without applying the ear directly, or by 
tlie inter^'etiiion of a stethoscope, to tho reapti-atory organs ; 
excepting when the mouth U chtsetl, and breathing is CLUTied 
on cxelujively through the nasal pikisages, when a soft, 
breezy murmur accoDipaniea both acts, If the nioulli be 
BuiHiiijently opened to admit the free passage of air, no eouad 
is to he heard in health. In sleep, the re&pirationa are un- 
usually profound ; and if tlie mouth be closed, the sound is 
rather more intense than usual. 

Snoring^ a peculiar Bound, more or leas marked, which 
6om«titncNi accompantea the respiratory acta during aleep, oc- 
t-uis when the air passes through both the mouth and the 
nose. It ia more marked in jnepiratioii, sonietiiues accoui- 
I'anying both act^ and Bometinies not beard in expiration. 
It IB not neee^ajy to describe the characters of a sound bo 

' lu listtining to tlic respiintoiy iBurniyr over tijc substance of the lunp, the 
0X|jinUn7 fuLlovs iLio ins)iiiuC(ir>' EOiiail wichciut aa LiUttiU (nas ]t. SUli). The 
inU'i-vwl butwL-an tliL- atHs of inspiration uid mpiratiun b only appreclivtHl u like 
sir puijice iti and out nt llio [uoiitli, 



394 



fiESFllEATlOM'. 



familiar. Snoring is. an idioBynvra^y with manj Individ nal?, 
though thoBG who do not eimre babitiially may do en when 
the system ia unusually exhausted and reluxed. It only oc- 
curs when the mouth is open, and the ftound is produL-ed by 
a vibraticm, ftnd sort of flapping, of tbe relum pendutum pa- 
latl between the two currents of air from the mouth and 
nose, together M'ith a vibration in the coluum of air itself. 

The auscultatory phenomena which aceojn|»nny the act of 
respiration have beeu made the subject of fipecial experiuicn- 
tal observatiouB by Dr. Flint, who, troin csircfully recorded 
examinations of a large number of healthy pereons, has ar- 
rived at the following conclusions: ' 

Applying the stetlioacope over the larynx or trachea, a 
eonnd is he.trd, of a distinctly jiud purely tubulrir chnracter, 
Bceompanyiug both acts of respiration. In inqjiration, "'it 
attains its maximum of intensity quickly after the develop- 
ment of the sound, and maintaina the eaine intensity to the 
close of tlie act, when the sound abruptly ends, as if sudden- 
ly cut otf." Alter a brief interval, the Bound of espiradon 
follows. This ia nleo tubular in qitjdity; it aoon attauiB its 
maximum of intensity, but, unlike the sound of inspiration, 
gradually dies away and is lost imperceptibly. It ia aeea 
that these phenomena correspond with the nature of the two 
acts of respiration. 

Sounds approximating in character to the foregoing are 
heard over tlie bronchial tubes before tliey penetrate the 
luDga. 

Over the substance of the lungs, a sound may be heard 
entirely different in its character from that heard over the 
larynx, Irachoa, or bronchial lubes. In inspiration, the sound 
is mu«h less intense than over the trachea, and has a breezy, 
Bxjiaiibive, or what is called in auscnltution a veaiaular char- 
actor. It is much lower in pitch than the tracheal sound. It 

' Flixt, P}i)fic!cai Fxptoratioa antl Diaifiiotit of DUeaiei ajff^inff Ad Bt^ 
miifrff Organs, riiiludL-lpliia, 186C, p. 13" ct jiy. >Vo giie bwt * brief aamniuj 
it iboM results, wb!<di aw speoiallT applinl to aoKjidUtiuii lu duealc 



395 



Is Cuntinuou^, and rutlier inijreaseg m iBteiitiity ij'otii its eoin- 
meuceiuent to its terniiiiation ; euding abruptly, 'lEko tlie 
traclieal inspiratory Boimd. Tlie Bound is produucd in part 
by tlie movement of air in the Braall bronchial tnbea, but 
chiefly by the expansion of the innumerable air-cells of the 
lungs. It ii folloired, without an interval, l>y the sound of 
expiration, ■which ib shorter, one-fifth to one-fourth as long, 
lower is pitch, and \'vry much less jntenst, A sound is uctt 
always, heard in expiratioQ. In tiileen examinations record- 
ed by Dr. Flint, five presented no expiratury sound. 

The variations in tlie intensity ol" the respiratory sounds 
in difl'erent iudiiiduala are very considerable. Aa a rule 
they are more intense in young persona; which has given 
rise to the term puerile re/>jnrati&n, ■when the sounds are 
exaggerated in parts of the lung, in certain ca&es of disease. 
The sounds are generally more intense in females than iu 
males, particularly iu tlie upper regions of the thorax. 

It is difficult by any description or comparison to convey 
an accurate idea of the character of the sounds heard over 
the lungs and ah'-puasages ; and it i& aupeiHuous to make the 
attempt, when they can he so easily studied iu the living 
aubjeet. 



Coughing^f Sneesing, Sitjhingy Yaicniiuj, Laughing^ &^hmg, 
and Hiccough. 

TTiesp peculiar acts demand a few words of explanation. 

Coughing and sneezing are generally iuvoluntary acta, 
produced by irritation in the air-tubea or nasal passages; 
though cough is ot^en voluntary. In both of these acts there 
ifl first a deep iuspiration, foUoWicd by convulsive action ot" 
the expiratory mupcles, by which the air ia violently ejcpelluil 
■with a eimracteristie sound, in the one case by the mouth, 
and in the other by the mouth and nares. Foreign bodies 
lodged in the air-paasages are frcfj^uently expelled in violent 
fits of coughing. In byperaecretiou of the bronchial mucoua 



396 BESPIRATIOIT. 

membrane, tlie accumulated mucus is carried by tbe act 
of coughing eitlier to tbe month, or well into the larynx, 
whence it is expelled by the act of expectoration. "When 
either of these acts is the result of irritation, either from a 
foreign substance or eecretions, it may be modified or partly 
Bmotbered by tlie will, but is not completely under control. 
The exquisite sensibility of the mucous membrane at 
the summit of the air-passages, under most circumstances, 
protects them froTn the entrance of foreign matter, both 
liquid and solid; for the slightest impression received by the 
membrane gives rise to a Wolent and invohintary cough, by 
which the offending matter is removed. The glottis is also 
spasmodically constricted. 

In sighing, a prolonged and deep inspiration is followed 
by a rapid and generally audible expiration. This occurs, as 
a general rule, once in from five to eight respiratory acta, 
for the purpose of changing the air in the lungs more com- 
pletely, and is due to an exaggeration of the cause which 
gives rise to the ordinary acts of respiration. "Wlien due 
to depressing emotions, it has the same cause ; for at such 
times, respiration is less effectually performed. Yawning 
is an analogous process, but differs from sighing in tlie 
fact that it is involuntary, and cannot be produced by an 
effort of the will It is characterized by a wide opening of 
the mouth, and a very profound inspiration. Yawning is 
generally assumed to be an evidence of fatigue, but it of1:eu 
occurs from a sort of contagion. ^Vhen not the result of 
imitation, it has the same exciting cause as sighing; viz., defi- 
cient oxygenation of the blood, and is followed by a sense of 
satisfaction, which shows that it meets some decided want on 
the part of the system. 

Laughing and sobbing, though expressing opposite condi- 
tions, are produced by very much the same mechanism. 
The characteristic sounds accompanying these acts are the 
result of short, rapid, and convulsive movements of tlie dia- 
phragm, accompanied by contractions of the muscles of the 



GAfK 



OF THE LUKOl 



307 



face, wliich produce the pxpreseions t-liaracterietic of liilarity 
or grief. Though to a certain extent under the control of 
the will, they avc mostly invuluiitary. Violent and convnl- 
sive laaghter may be excited in many individualB by titilla- 
tion of certain portions of tho surtaco of the body. Lautrh- 
ter and eometimes eohhing, like yawning, may be the result 
of involuntary imitatloti. 

Hiccough IB a peculiar modilication of the act of inspim- 
tioHj to which it i* exi/lusively confined. It la produced by 
a sadden, commlsive, and entii-cly involuntary contraction of 
the dtaphrngm, accompanied by a ppaemodic constriction of 
the glottis. The youtractlon of the diaphragm is more estcn- 
ave than in laughing and sobbing, aud occure only'oni^B in 
four or five rcapiratory acts. Tlie eansea which give rise to 
hit-cough ai'e numerous, and many of them are referable to 
the dtgeative system, Among these may be mentioned the 
rapid ingestion of ft quantity of dry food, or of effci'vesL-ing or 
ftluoholic drinks. It ocuura l&'equently in cases of disease, 



Capacitij of tfie L\mgs, and the Quantity qf Air cAanged in 
the Iie$2nratory Acte. 

Several points of c-ouBiderable phyBiological interest arise 
in this connection. It fs evident from the simple eiperimcnt 
of opening the chest, when the elastic lungs collapse and es- 
pel a certain quantity ctt' air which caniiut be removed u'hile 
the lungs are m sttUy that a pai't of the gaseous contents of 
thoAe organs necessarily remajos attor the most complete and 
forcible esptration, AlW an ordinary e.tpiration, there is a 
certain quantity of air in the lungs which can he expelled by 
a (breed exjiiration. In ordinary j-espiration, a comparatively 
email vohime of air is introduced with inspiration^ which is 
expelled by the Bucceeding expiration/ By the extreme action 

' Eipcri.meDts hare slioira that a ci^rtun vulune of air is lost m \h^ Lunge, 
\h* ex^Kd lir Iwiug a liiOi; k-aa iu volume llwn the qu:\iitiij im-pircd ^froin '^ 
to 1^), Tliid is not [iilci!ii into account in thU cooDet^o-n. 
SO 



StfQ BESFIKAIKUl. 

of all tlie inspiratory iiiuscles iq a forced inspi ration, a sup- 
plemental quantity of air luuy be iutrodaeed into tlie longs, 
which then uoulain much more than tliej ever do in ordl- 
narj- respiration. For conveuieot^, many physiologists have 
adopted the follo\Tiug naoieei, ^Uicli are appltcsd to these 
v,-u-ious volumes of air: 

1. Ilestd-u<d Air J that wliicb is not, and cannot be, ex- 
pelled liy a forced expiration. 

2. Meserue Air; that which remains after an ordinary 
exi)iru.tlon, dediieting thi3 rei^idual air. . 

3. Tidal^ or ^rdinar^ Sreathing Air; that which is 
clianged by the ordiBarj actfi of inspiration and expiration. 

4. CoinjtUmefikd Air; tlie excess over the ordlnnrr 
breathing air, whiili maj/ be introduced by a forciblo in^pi- 
Ritiuu. 



The questions relating to the above divisions of tlie re- 
spired air have been made the subject of numerous iavestlga- 

tioiis; but though at first it might seem easy to dctennine all 
of them by a sutfieient number of experiments, the neeessary 
abservationa are attended with considerable difficulty, and the 
sources of error are numerous. In meaauring tije air changed 
in ordinarj' brealhitig, it Iijw liecti found that the acts of res- 
piration, are bo ea&ily iiitlntru-t-d by the mind, and it is so 
diOicult to experiment on any individual without his knowl- 
edge, that lliQ results of many good observers are not to he 
rchod upon. This i& one of Lbo most important of the qaes- 
tiona under eonslderalion. The difficulties in the way of 
estimating with accuracy the residuaE, reserve, or comple- 
inc-iit:d volumes, will reatlilj suggest themselves. Tlie «b- 
&ervatioiia on these poiiita, which may he taken as ihe most 
definite and exact, are tbo^o of Herijst of Gcittingen, and 
Hutyhiuson of England,' Those of the lasl-natncd observer 

' AsuBunatjoF tb.c nb.tAriitiDnaorHerbet, tniu^6 id 1828, la to hefouu'S In thf 
Ar^ivu QiniraUt de Mitlediu, |ocu« zxt, p~ 412. The obMmttiwm uf BuUlh 



BESEBTE AIB. 399 

are exceedingly elaborate, aud were made on an immense 
number of subjects of both sexes, and of all ages and oecu}>ar 
tions. They are generally accepted by physiologists aa the 
most extended and accurate. 

Setidiial Air. — Perhaps there is not one of the questiona 
under consideration more difficult to answer definitely than 
that of the quantity of air which remains in the hings alter a 
forced expiration ; bnt fortunately it is not one of any great 
practical importance. The residual air remains in the lungs 
as a physical tiecessity. The lungs are always, in health, in 
contact with the walls of the thorax ; and when this cavity 
is reduced to its smallest dimensions, it is impossible that 
any more air should be expelled. The volume which thus 
remains has been variously estimated at from 40 cubic inches 
(Fontana) to 220 cubic inches (Jurin), Dr. Hutchinson, who 
has caretuUy considered tliis point, estimates the residual 
volume at about 100 cubic inclics, but states that it varies 
very considerably in diflferent imJi^-idnals. Taking every 
thing into consideration, we may assume this estimate to be 
as nearly correct as any. It is certain that the lungs of a 
man of ordinary size, at their minimum of distention, contain 
more than 40 cubic inches of air ; and from measurements 
of the capacity of the thorax, deducting the estimated space 
occupied by the heart and vessels and the parenchyma of 
the lungs, it is shown that the residual air cannot aniuunt to 
aiiy thing like 200 cubic inclies.' 

There is no special division of the function of res- 
piration connected with the residual air. It remains iu 
the lungs mei-ely as a pliysical necessity, and its volume 
most not be taken into account in considering tlie vohimes 

liuKin ue contained fn exieiuo in the Ci/ilojKFtHa of Aiifi(oiiii/ and Fkytioioiji/, rol. 
Iv., part 1, uticlo Thorax. 

' fintchlnson foiuul the meua abiiolulc cti]MiL'ity of the thorax to be 312 cubie 
ineheB. He aUows 100 cubic inches for the heart and blood-TuiMcU, and 10<) ibr 
the puenchTioa of the tungs, IcaviDj; about IdO for the residual rolunie Op. eil., 
p. KM. 



400 KzapiBAiio^. 

which are changed in any of the operations connected \nth 
breathing, 

Begerve Air. — This name is appropriately given to the 
volume of air which may be expeUed and changed by a vol- 
untary effort, but which remains in the longs, added to the 
residual air, after an ordinary act of expiration. It may be 
estimated, without any reference to the residual air, by for- 
cibly expelling air from the lungs, aflier an ordinary expira- 
tion. The average volume is 100 cubic inches.' 

The reserve air is changed whenever we experience a 
necessity for a more complete renovation of the contents of 
the lungs than ordinary. It is encroached upon in the unu- 
sually profound inspiration and expiration which occur every 
five or six acts. It is used in certain prolonged vocal efforts, 
in blowing, etc. 

Added to the residual air, it constitutes the minimum 
capacity of the lungs in ordinary respiration. As it is con- 
tinually receiving watery vapor and carbonic acid, it is always 
more or less ^tiated ; and when reenforced by the breathing 
air, wliich enters with inspiration, is continually in circulation, 
in obedience to the law of the diffusion of gases. Those who 
are in the habit of arresting respiration for a time, as the 
pearl-diver, learn to change the reserve air as completely as 
possible by several forcible acts, and then fill the lungs with 
fresh air. In this way they are enabled to suspend the re- 
spiratory acts for from one to two minutes without inconven- 
ience. The introduction of the fresh air with each inspira- 
tion, and tlie constant diffusion which is going on and by 
which the proper quantity of oxygen finds its way to the air- 
cells, give, in ordinarj' breathing, a composition to the air 
in the deepest portions of the lungs which insures a constant 
aeration of the blood. The slight difference in the rapidity 
of oxidation between inspiration and expiration is only suffi- 
cient to give rise to the involuntary reflex acts of respiration, 

' HCTCHINSOS, loc. eU. 



COMPLEMENTAX AIR. 401 

and IB not suffiuientlj marked to produce any Bensation, such 
OB is experienced when respiration is in the slightest decree 
interrapted. 

TideUj or Ordinary Sreathing Air. — The vohinie of 
air which is changed in the ordinary acta of respiration is 
Biibject to immense physiological variations, and the respira- 
tory movements, as regards intensity, are so easily influenced 
by the mind, that great care is necessary to avoid error in 
estimating the volume of ordinary breathing air. The esti- 
mates of Herbst and of Hutchinson are the results of very 
extended observations made with great care, and are gener- 
ally acknowledged to be as nearly accurate as possible. As 
a mean of these observations, it has been found that the 
average volume of breathing air, in a man of ordinary stat- 
ure, is 20 cubic inches. According to Ilutchinson, in perfect 
repose, when the respiratory movements are hardly percep- 
tible, not more than from 7 to 12 cubic inches are changed ; 
while, under excitement, he lias seen the volume increased to 
77 cubic inches. Of course the latter is temporary.' Herbsl 
noted that the breathing volume is constantly increased in 
proportion to the stature of the individual, and bears no defi- 
nite relation to the apparent capacity of the chest. 

OnnpUmentdl Air. — The thorax may be so enlarged by 
an extreme voluntary inspiratorj- effort, iis to contain a quan- 
tity of air much larger than alter an ordinary inspiration. 
The additional volume of air thus taken in may be estimated 
bj measuring all the air which can be expelled from the 
lungs after the most profound inspiration, and deducting tlie 
Bum of the reserve air and breathing air. This quantity has 
beoi found by Ilatchinson to vary in different individuals, 
bearing a close relation to stature. The mean complemental 
volame is 110 cubic inches. 

Tlie complemental air is drawn upon whenever an effort 

' We hare not thought it vortli while to ciiiimcratu the varied ojitimatcs Touud 
In woritB on phTaiology, which are not baaod on cxtcncled eiperimentiU iuqiiirr. 



40S EE3PTR4TI0S. 

IB made wbk'li reiniii'es a temijorary arrest of reBpiratJon. 
Brief and vtolent iHiiseular escrtion id generally preeeJed by 
a prot'iHind inspiration. In aleep, as the volume of brcHthinf; 
air i$ somewhat iucreaaed, tlie compleaicntal air is encroaelitKi 
np(.>D. A part or tlie whole of the complemental air is also 
used in certain "vocal efforts, in blowing, in yawning, in the 
deep inspiration which precedes sneezing, in etraining^ etc. 

Svmmari/. — In a healthy male vf medinm stature, the 
residval ah; ivhifh tamiot he expelled fri>tn the lunge, 
amounts to ahont 100 enbic inohea. 

The resenv ait% -wliich can be expelled, but which is uot 
cbsiiged In ordinary respiration, atnouots to about 100 cubic 
indies. 

Tiie tidal air^ which ia changed in ordinary respimtton, 
amounts to about 20 cubic inches. 

Tlie complemenial air, whitli may be taken into the 
lungs after the completion of an ordinary act of inspiration, 
amounts to about 110 cubic inches.' 

' In Rabin's </uiirna( tie PAnatuiHiB eC de la Phjftiuioffie^ ScjfL I3M, p. SU 
ti trq., we find no nriii^li; bjr Dr. N««lor Gr^tiaut, on llie> |iEij'sii.'itI pli^nuinaiB 
of reS|jimlloii in mAn, nhii'ln Mm'l^Da eume niivd and interesting ul>8«ntati(>nt UQ 
the cnpncit; of tbp I'l-Q^, ^otuine of brcalliiag ■ir, etc, Tfai? voltimot uT njr sf* 
esUointcd by n proccea which \a cicwdiogly iogcoiaiif, anil appuvnily nceurfttc ; 
but the number of obseTvatiiim ia vvry email h-oiuikitwI with Wiois of Uuh^liiuon, 
uad ill eatimutiiig llic vitj)Bi:i[y of tbe luo^^ lie <lwti uot iiikc inio consitli'Tstlon 
tilt vtrv dmded influciico of stature. Tlie method employed ia esscniuill^ the 
following : 

It hariDt! Iietn demonat railed by JEcgniiiilt and Reiset thm hydrOgea ititn>- 
duced into the luuga In not a>>!'i>rl>L-il by (he blorxl, Lhi' author, bilcing adTBatage 
of the wvH-luiown prnptirty of gases, liy nbicli ttiL'y fonn a uniform miiUite when 
bmuglit in L-OQtuct wiiU each other, cauBed the subject* Qf his eiperinioata to n> 
tplre • muaBur^ vulutnc of bjdrogeu often enough to Dial(L> tfie miitiire uniforra, 
&iiJ eatJmiHtM, by aiialysia of tlie enpired lur, the rjumtiij wh>«h ivniaitiB to the 
liin^, wliich ia ne>(^sarily ivpruscnicd by tbv voIciiiig of hydrogtiD lost. Be i» 
ecitaincd by cxperitaenta iLiiit five n^pLratioDS of the gas caused a perfect 
mLituie. 

By ihJa tuelboil bo c.'^ttjimtta lli« botmal cjt[)di:i(y of th« lungs anef an onb- 
ttary vxinrsdon {tb« sum of Iho residual utid reserve aLr), at froiA I38*9& to IVI'Bl 
cubir invhtifl, ia men b«ti*een 1? uid 80 years of age (^ 504}. 



I 



EXTBEHE B£EArUC\G OAPACm*. 403 

Extreme Breathing Capacity. — By tlie extreme breathing 

capacity is meant tbeVoluuie of air which can be expelled 

€tqt(i the lungs by the most forcible expiration, after the most 

2>rofomid inspiration. Tliia has been called by Dr. Ilutciiin- 

^son the vital cajHicitj/j as signifying " the volutiie of air 

"^which can be displaced by living movements." Its volume 

ms equal to the snm of the reserve air, the breathing air, and 

'ftibe complemental air, and represents the extreme capacity 

of the chest, deducting the residual air. Its physiological 

'Snteroat is due to the fact that it can readily be determined 

TL)y an appropriate apparatus, the spirometer,' and compjiri- 

^3ons can thus be made between diiferent individuals, both 

l^ealtby and diseased. The number of observations on this 

2point made by Dr. Hutchinson is enormous, amounting in 

s&ll to little short oi jive thousand. 

The extreme breathing capacity in health is subject to 

"^rariations wliich have been shown to bear a very close rela- 

"tion to the stature of the individual. Hutchinson com- 

niences with the proposition that in a man of jnedtum height 

Kj& feet 8 inches), it is equal to Uco hundred and thirty cubic 

■inches. He has shown that the extreme breathing capacity 

Is constant in the same individual, and that it is not to be 

increased by habit or practice. 

The most striking result of the experiments of Dr. 
Hutchtnaon, with regard to the modifications of the vital ca- 

The tidftl or breathing lur, lio cBtimates at 30 cubic inchcD. 

The oboerratioDB of Dr. Ur^hunt are as vet so few in niimbtT tliat wp pri'fpr 
to fldbere to the results of the greatly [?xti'U'Jo(l obscnaliuns of Hiitdiiiison ; 
thougfa the new method id very ingenious, ami i'lirtlier esi>eriinenis will pniliubly 
letd to important resulls. 

* TheipirametncoDsist^of avcssel eoDlaining water, out of which ^rfceiver 
!■ T^ied by brenthing into it throu;:h a tulte ; tlie liei^iit to which Ihc rvi-eivcr is 
niied indicating the volume of tlie vitil capacity {f'l/d-ji. of Anal, and I'hy*., 
nd. It,, part 2, p. 10G6). In all the obscrvaliuns of Dr. Ilutchinsun, he has tuken 
ean to see that tlie level of the water was the piinie in the receiver and the re.^ei^ 
voir, and to carefiilly correct the voIuiqce of air for lenii>eroturc. All obscna- 
Dons weio made with the subject erect, and every thing carefully avoided which 
•ooid Interfft'e with the free action of the respiratory luiisde^ 



104 



ItESPIBATlOK. 



pacitv, id that it lieara a definite rt-lfttiun to etatnre, willioiit 
bemi; atfijtited in a very iiiurktid dpgrt-e by weight, or tbe 
eircumtbi'oDCje of tbe eliest. This is esjiecially rciiiurkiible, ae 
it is well known tli.it Leigbt does not ilcpcud so miioli upon 
the length of the body, as the length of the lower extremities. 

It hm leen agcei'iain^d tfiai for every inch in hdgfu, h^ 
tween Jive and tfcx fetf, ifie e^treni^ hrcdUhmg cupacity is t«- 
oreitaed eir/ht vuh'w inehfs. 

The following tiible &hows the me^iD results of the im- 
nienijc niiiiibcr of obgervntioDS on which this concluaiun ts 
based: ' 

pTfHjresslon of the Vital Capacity Vbluinii tcriih the Stature. 



let^llL 



S ittX inches 



U fiwl 1 !»c]i, 



H'CBi] of alt Qei|;lits. 



lit mat. 

tvo-o 



•nA« 



176-0 



ai7o 



SI 4-0 



Age has an influence, though less marked than etature, 
apon the extreme breatliing capacity. Aa the result of 4.SO0 

' Oi). at., p. lOTa, The iDcn»0e iu brmtbing apadtr. pon yamm -m'na in 
Incrnise In lieight. was uicationet] by lltrbst !,f(K. eit,), bill Butchituon wm th« 
fint to miike nny citended observotiDus, nnd glie any defiuite infoTnulivD an 
«b point. 



EXTBEUE BBBA-nOHa OA.PACr[l'. 



405 



obBervntiona (males), it was ascertuiued tlmt the vohiiiie in- 
ereasL'S with age up to tlio tliirtietli year, and progrt-ssivcly 
decreaacfl, with tolerable regularity, from the thlriietih to the 
eistieth year. 

These Hgutee, though neces&arlly eiibject to certain ijidi- 
vi'diiHl variatloiie, may be taken as ttie basis fur exaniiuatloiiB 
of the extreitio hreathiug capacity in disease, which frequently 
give important iiiJormation. Of course, the breathing uapa 
city ia modified hy any abnormiil coTidition wliicli interferes 
with thti mobility of the thorax, or the dilatubility of the 
'ungs. Of all dieeaaed conditions, phthisis puliiioiialis is the 
most interestbig in thta connection. With regard to the 
signitiyaDL-e uf tlie Tariations iu this diBCuaet Dr. Hutchinson 
has arrived at the following eonclusiona : 

" It has been foucd that ten cubit! inches l>elow the due 
quantity, i. c, 220 instead of 230 inches, need not excite 
III arm ; but there is a point of deficiency in the breathing 
volume at wliich it is difficult to aay whether it is merely 
one of those phy&iological diflerences dependent on a certain 
irregularity in all suyh observatione, or deliciency indioitive 
of diseaee. A deficiency of 10 per ceut. is suspicious. A 
man below 55 years of age breathing 103 cubic inches instead 
of 230 cubic inches, unless he ia exceseirely fat, is probably 
the subject of disease. 

" In phthisis pulmonalis the dcHcieuc}* may amount to 
90 per cent., and jet lite be maintained. The vital capacity 
volume ia likewise a measuro of improvement, A j>hthisicfll 
patient may improve bo aa to gftin4o upon 220 cubic inches." 

Ilerbat has shown ' that tlie extreme breathing capncity 
is diniiniahed by obesity; that it is proportioually lees in 
females than in inaleB, and in cliildrcn titan in adults. 

JteUiiions in Yolurne of iJie Exjfired to the In»pired Air. 
— A certain proportion of the inspired air is lost in rK])ira- 
tion, 80 that the air expired is nhrnja a little Iras in volume 

' Loc. o'i. 



406 EESPIEATION. 

than that which is taken into the lungs. All the older ex- 
perimenters, except Magendie, were agreed npon this point. 
The loss was put by Davy at ^, and by Cavier at -^ of the 
amount of air introduced.' Observations on this point, to be 
exact, must include a considerable number of respiratory 
acts; and from the difficulty of continuing respiration in a 
perfectly regular and normal manner, when the attention is di- 
rected to that fiinction, the most accurate results may prob- 
ably be obtained from experiments on animals. Despretz * 
caused six young rabbits to respire for two hours in a con- 
fined space cjjntaining 299 cubic inches of air, and ascertained 
that the volume had diminished 61 cubic inches, or a little 
more than one-fiftieth. We may take the approximations of 
Davy and Ouvier, as applied to the human subject, as nearly 
correct, and assume that in the lungs, from -^ to ^ of the 
inspired air is lost. 

Diffusion of Air m the Lungs. — ^When it is considered 
that with each inspiration but about twenty cubic inches of 
fresh air is introduced, suflScient only to fill the trachea and 
larger bronchial tubes, it is evident that some forces must act 
by which this fresh air finds its way into the air-cells, and the 
vitiated air is brought into tlie larger tubes, to be expelled 
with the succeeding expiration. The expired air may be- 
come so charged with noxious gases, by holding the breath 
for a few seconds, that when collected in a receiver under 
water, it is incapable of supporting combustion. 

The interchange between the fresh air in the upper portions 
of tbe respiratory apparatus and the air in the deeper parts 
of the lungs is constantly going on, in obedience to the well- 
known law of the diflfusion of gases, aided by the active cur- 
rents or impulses produced by the alternate movements of 
the chest. When two gases, or mixtures of gases, of different 
densities are brought in contact with each other, they diffuse 

' ItLRADD, Court de FhytiologU, Paris, 18B1, tome uL, p. 8S& 
* Idem. 



DIFFl'SIOK OF AIK DT THE LUSQ8. 407 

or mingle with great rapidity, nntil, if undisturbed, the whole 
mass has a uniform density and composition. This has been 
shown to take place between yery light and very heavy gases 
in opposition to the laws of gravity, and even when two res- 
ervoirs are connected by a sniall tube many feet in length, 
though then it proceeds quite slowly. In the respiratory aj*- 
paratOB, at the termination of inspiration, the atmospheric 
air, composed of a mixture of oxygen and nitrogen, is intro- 
duced into the tubes with a considerable impetus, and is 
brought into contact with the gas in the lungs, which is 
much heavier, as it contains a considerable quantity uf car- 
bonic acid. Diifusion then takes place, aided by the clastic 
lungs, which are gradually forcing the gaseous contents out 
of the cells, until a certain portion of the air loaded with 
carbonic acid finds its way to the larger tubes, to be thrown 
off in expiration, its place being supplied by the fresh air. 

In obedience to the law established by Graliam, that the 
diffusibility of gases is inversely proportionate to the square 
root of their densities, the penetration of atmosplieric air, 
which is the lighter gas, to tlie deep portions of the lungs 
■would take place with greater rapidity than the ascent of the 
air charged with carbonic acid ; so that SI parts of carbonic 
acid should be replaced by 95 of oxygen.' It is found, in- 
deed, that the volume of carlwnic acid exhalwl is alwa_)s Iqss 
than the voluTJie of oxygen absorljcd. 

This diifusion is constantly going on, so that the air in 
the pulmonary vesicles, where the interchange of gai^es with 
the blood takes place, maintains a pretty uniform composi- 
tion. The process of aeration of the blood, thorefbrc, has 
uoue of that intermittent character wliich attends tlie ine- 
cfaanical processes of respiration, which woidd undoubtedly 
occur if the entire gaseous contents of the lungs were changed 
with every act. 

There is no evidence suffieiently definite to show that the 
muscular fibres in the bronchial tubes, which are of the mi- 

' Cjfdopadia of Anatomy aiid I'liifvlology, vol iv., part 1, p. ^6^. 



408 



BE8PIRATI0K. 



Striped variety, and slow aud gradnal in their contraction, 
have any thing to do with the diffusion of gases in the lungs ; 
nor is it probable that any marked influence is exerted by 
the movements of the cilia which cover the mucous mem- 
brane. 




CHAPTER XII. 

CHANGES TTHIOH THE AIB UNDEEGOE3 IN BE8PIEATI0S. 

Qenenl conndentiona — Discoveiy of carbooio acid — DiscoTery of oiygen — Coot- 
pondon of the air — Consumption of osygen — ^loflueace of temperature — In- 
fluence of Bleep — Influence of an increased proportion of oxygen in the atmos- 
phere—Temperature of the expired air — Exhalation of carbonic acid — Influence 
of ago— Influence of aei — Influence of digestion — Influence of diet — Influence 
of Bleep— Inflnence of-muacular activity — Influence of moisture and tcm< 
perature — Influence of seasons — Relations l>etwecn the quantity of oxygen 
conanmed and the quantity of carbonic acid exhaled — ^Exhalation of watery 
Tapor— ExhalalioQ of ammonia — Exhalation of organic matter — Exhalation 
<tflutrogen. 

Fkom the allusions wliicli have already been made to tlie 
general process of r^piration, it is apparent, that before the 
discovery of the nature of the gases which compose the air 
and those which are exlialed from the lungs, it was inipo^ible 
for physiologists to have any correct ideas of the nature of 
this important function. It is not surprising that the ancients, 
observing the r^ular introduction of air into the lungs, and 
noting the fact that the air is generally much cooler than the 
body, supposed the great object of respiration to be the cool- 
ing of the blood. It is also evident that no definite knowl 
edge of any of the processes of respiration could exist prior 
to the discovery of the circulation of the blood. 

Though it is foreign to our purpose to treat historically 
of fhe theories concerning any of the functions of the body 
the fiwjtfl relating to changes in the respired air, which from 



iiu 



RR^riEATJON, 



[ime to time hfive bepn dcvelupeil, bear so close a relntion tu 
diseuverie& of the properties of certain gases, particularly 
carbonic acid and ox^vgen, tliat it seeras desiralile to give at! 
least a rnpid feketcli of tlieao diw^overiea, smd follow tlie ad- 
vances iu our knowledge of the proceBses of respiration, with 
which they are necessarily cyiihetted.' 

In tlte latter part of the litleenth century, Leimardo da 
Tiuci, the great painter, mathematician^ and naturalifct, made 
a discovery which conclusively proved the fallaiiy of the idea ^ 
that the air simply cooled the Mood iu respiration. He di*- ^M 
covered that tire consumed the air, and that auiuinis could ^ 
not live in a medium wliicli was incapable of supporting 
combustion. This is the first atatcment iu the history of 
aeience which points to the fact that the fiinetiiin of the air 
ill respiration depends on its eompoieiliou, and not vu ita^ 
physical properties. 

About the middle of the seventeenth centup}'. Van Kel- 
mout discovered some of the projiertles of what is now known 
aa carbonic acid gas. He showed that a gas, the result of 
fermentation, or of tl»e combustion of carbon, and formetl by 
the action of vinegar on certain carbonates, was incapable of 
eupporting combustion or maintaining animal life. Ho rec- 
ognized this as the gas which is found in the (ower jmrt of 
the celebrated Grotto dd Cane, near Naples, into whicha man 
may enter with impunity, but which will asphyxiate a email 
animal, as it is brought under the influence of the lower strata. 

A few years later {1670), Doylc, the founder of the Royal 
Society of London, by some ejqjerimenta published in (he 
Philosophical Tramaf^iiontiy attempted to ghuw that air waa 
iiecefsary to the life of all animals, even tho&e which livo 
under water. In a remarkable paper entitJed -Suxj/icicfn^ 
ab&ut some Hulden Qualities of the Air, he pointed to the 



' The render Is tcfejTeJ lo tb« oltlxinitc wort of MiLKE-BnwuiDe (Zcjvn* mir 
la Fhiflialoffie, tome i., p. 376 tl ng.) for a. camplclc uiid tii^lily inhreadiiE historj 
of the pbiyiaiulugy of rrspintrJon, from which im liavo Ukcu most of the titetorial 
lactA to irlucb refcrenoe irill b« made. 



CBASGES IN THK AIR D.' REBPIKATION. 



411 



probable existence of somo unknown vital subatance in the 
atmosphere. A i'evr yean later it wiis ileiuLiustrated by Ber- 
iioulli. that tlie esistent-e of aquatic animals depends upon 
air held la solution in tlie water. About tbis timo Robert 
Hook performed liis celebrated experiuient of exposing tlie 
lungs of a, living animal, and maintaining tlie vital processea 
hy artificial respirotiou. He demonstrated that aeplivxin 
occurred when be ceaived to change the air in tlic lungs, 
though these organs were allowwl to remain distended, 

Fracasaati also showed that the red color of the upper 
Burface of a dot uf blood was due to its exposure to the air; 
and Lower, examining the blood before and after it& passage 
through the lungs, in artiticial respiration, sliowed that the 
red color of arterial blood depends on tiie reuowal of the 
atmosphere. 

In 1667, Ma^'ow pubHshetl hla work on Uespiratior, in 
which he advanced the view tliat the air contained a prinei- 
ple, capable i^f supporting comhustion, wliifh is absorbed in 
respiration, changes venous into arterial blood, and is the 
cause of the heat which is developed in aniniflt bodic'S.' Tlie 
importance of this djacuvcry was not appreciated by the phys- 
iologists of that day ; and It was more than a uentury before 
it received its appiopriale place in science. 

In 1757, Joseph Blank, of Glo.'igow, isolated and studied 
carlwnie acid, whieh he v.a\Wd Jlxed air. He reco^ized this 
las in the expired air, by passing the breatli through liui©- 



' We Gad the fallovfbiie pnssn;^ in an an&lyaia of tlie work or Hatott on Aa 
jAndiqu^ piililii^licd in the rhtiruapfiUrai Tranxattion*. lUfiS, p. 833 : 

" The :iittlicir • • • delivers liis IhOughla on Ihu «St nf Resfjiratioti, WAVibg 
the*? opinioLui, tbat would hnve retipiratioc either to cOol clic hear-t, or aialie tlie 
Cloui) pf^x tbrougL tlie Lungs out or dm riglsl ventricle of ibc l»»rt lo Che le^ 
hr to rc4ilCC th-e thii'kcr veoal blood Lntn tliinner and finer parts; anil atlirtiiinfr, 
Tkat lliLTf i^ Eontt-'lhing in tliv Air, aib«i)liitcljr net-c^sarj lo lil'e,, wliiul is cunvej-ed 
btto U>e Blond; n}iiL<1i, whatever it ha, \>Aag cihaualvd, tht rest of llii: lir in 
timde tudiwf, nnil no mtiru tit f<jr Reain-imiiuo. Where yet U« doth nut exi'latSe 
Ihid iise, Ttmt nitli ihi- npuUuil jlir, thi! vapors aiuo, steaming oM of the Blauit, 
iiru thrown out logi.'tlier.''' 



419 



EESPraATTON. 



water. It is evident tbat tbU wa^ tlie gas whicU v&6 ol^ 
BerveU so many years before by Viin Ilelraont. 

Iq 1775, Priestley discovered that tlie air is compowd of 
oxy^a and nitrogcD, tlioiigli be did not make u^e of tlieee 
names; and a few yeais later, ehowed that air wliicli lias 
Iteen vitiated by ihe respiration of aniaials 'm consumed Uy 
vegetables, which return the elements neoessary to the life of 
anitnaU. Iq s paper published in the Philogoph!cal TranMc- 
tion« for 17T6, he proved that thu change in the color of the 
blood in the luDge is due to the absorption of the newly 
discovered oiygen ; and showed, furthermore, tliat tlie inter- 
change of gases betweeD the air and the blood can take plaoo 
tlirough niembniiies, as readily as when the two fiuids an 
brought directly in contact with each other.' 

The discoveries above enumerated, though all bearing on 
the great question, were simply isolated fauts, and failed to 
develop any definite idea of the chmiges of the air and blood 
in Inspiration. The application of th{«c fact^ wng made by 
the great cbeioist Lavoisier; who wa* the tir^t to employ the 
delicate balance in chemical inrestigatioD, and whose obser- 
TatioQs m,ark the beginning of an. accumte knowledge of \Xvt 
function of respiration. With the balance, Laroiaer ebowed 
Hie nature of the oxides of the metals ; he disoorered that 
carbonic acid is formed by a union of carbon and oxygeo; 
and, noting the consumption of oxygen and the prudnctioa 
of carbonic acid in reapiratioa, advanced, for the first tin», 
the view that tlje one waa employed in the pnxlactioa of tlw 



* B^AKo ittnbBlM the discoTti; of oifgea xa Bajea (op. dL, Cane A, 9. 
It8> li u tnw ihu B&jm ia 1)74 emlnd oi^gm b; beafiBg the ted oxiia tt 
atonu?, but be rinplT eaw & gu pnai •>!£ the umk ud f a paii eg t€ wUA W 
fid not de«mb«. Pfwetlej bM |inhHnliri1 bii Steaitvj of ^ixTEm, bM « dwry 
6cm tf/<wlmin of lA irmporlaat f n piTtt M^ m Ihc auDc t«*f ; tAd hgwi hm ^m» 
deaeribed Tn^wrties Blurb dWtinggah Qat fraa rrrrj Otber gam, t* F^imHtf b 
gBomwBf, vid jattlj, MCRb«d the iMnar of ib d&aeantj. Sdhedbv fa Svadio, 
obcuncd and dMoribcd oij^ra ("Otm air dt &n'^ abortl? afiv k kad lien ob 
ttkwd byr>teU<y,atilhgM«thgbw«te^tlMltMdb«|irgT'**J>*w«»Mp"Wd 
K» WW*. WW fMUbti in IT'T. 



COSIPOSmOS OF THE Am. 



413 



other. Though, as would naturally be esiiected, the (loo 
tritieg of tiiU great oLisiTTtr liave been mtKlitied wlUi tliP 
advances iu scieute, he developed facta which will atimd fur 
ever, and wliich Iiave served as the starting poiut of all 
oar knowledge on this &iihje«t. From that time physji^l- 
ovists be<;an to luok on rcapimtjuu as eoustHtiog iii the appro 
priation of oxygen and the exhalation of oarbonia acid 
and now the seat of tUra procesa ia only changed from tlie 
lung^i to the tissuea. From the limited knowledge of the 
intimate phenomena of nutrition which obtained in. his day, 
Lavoisier could not be expected to entertain any other view 
than that the carbonic acid produced was the re&ult of the 
direct union of oxygen with carbon in the blood. It is only 
since inTeatij;;ntionB have made manifest the great uoinploxity 
of the proeesara of nutrition, tlmt some are unwilling to be- 
lieve that civrlwuic acid ia produced in aa sinipEe a way aa 
it appeared to Lavoisier.' 

Cftrnpoiition of t?i6 Air. — Pure atmoBpherii.- air is a 
ntechanical mixture of TO-10 purts of nitrogen with 20'81 
parts of oxygen (Dunuis and Boussingault).* It contains in 
aildition a very aniall quantity of carbonic auid, about one 
part ID 9,000 liy volume, and tracea of ammonia. The air 
is never free from moisture, which is v<?ry %*arinbie in quan- 
tity, being genei'ally umre abundant at a high than at a low 
temperature, In IS-Ht, Schoubcin discovered in the air a pecu- 
liar odorous princij>Ie trailed ozone, which he conceived to Imj a 
compouud of oxygeu and hydrogen (HO,), but which is now 
pretty well shown to be an allotropic ibrm of oxygen. Tho 

' Thtf applicaljans of the *liBCOTi.>riM of LiLVoi.'=kr to lh« production ^f uniia^ 
AHt will be taken up ia ronni^ciion with ihat phi^inofncnon. 

' Some (iiL'iniate aiippoitc tlinL the oiygiMi &\u\ bitrogen ia Cbe »ir are in a cAi^ 
diljou of fi'i-ttle i::hfiiiicitl i^OTiiliinai.u)». Ilnwever Hint maj im, it is certain Lbnt 
in re*ipicntiun it is Ihi- oijgun uliid] ia ol.i&orlwjJ Lj tlie blooi), Mid wkiicti tainiei 
on the Oiurtioii. Tlie mtro^L'u 8t-c'nir« tu ant f^imply as ai dtluuitr, time providing 
thai tlie bidod in iho lungs sIiaU ha exposed to btil it ctH'tuiD i|iiuitil; of Ihe re- 
)|riraiOT7 priudplcL 

37 



J 



4U 



BEBPIBATIOH". 



oxygen which is obtained by decomiKssiTig water by the Vol- 
t>iie pile U iu tbia eondition. It exists in very small q«:Mitity 
in lliu air, aiui plays no part in the ftinction of respiration. 
Its chief interest has been in a, tlieoretiral connection wisb 
epidemic digeas^.' I'loatitig iu tlie atmosphere arc n nuin 
ber of exueesively minute organic bodies. Various odur- 
ous and other guseoiia matter may be present as acuideatal 
const itu cuts. 

Iu considering the function of ijespinitlon, it is not neces- 
Bary to take acomut of any of the fonatitut'uts of the ariuos- 
phere, except oxyj^n and nitrogen ; the others being' either 
incioastant, or existing Jii esectisiveiy minute quantity. It 
ia necessary to the regular perfoTtuanee of the function that 
the air should uoutaiii abniit ioiir parts of nitrogen to one of 
oxygen, aud have abuut the density which exLita oq tlie gen- 
eral auriuce of the globe, Wlieu tlio density ia very much 
increased, aa in luin'Cii. respiration is Bomowbat, though not 
gravely^ disturbed. By exposure to a rarefied atiuosphere, aa 
in the ascent of high nionutaina or in aerial voyagK., rcepim- 
tion may be very serioualy iutcrlercd with^ from the fa^l that 
leeis oxygen than iisual ia presented to the respiratory surface, 
and the reduced atmospheric pressure diiuinishee the cajM* 
city of the bluod for holding gases in suhition. 

Magendie and Beniai"d, in exiJcrinieutiug on the roinlmiira 
proportion of oxygen in the air which is capable of eustaiuing 
litl'j found that a rabbit, wmtiued under a licll-glasa witJi an 
arrangement for removing the carbonic acid and water ex- 



* Ozone mu7 be Tonticd by pikuing elertrie difdiarpH diKM^ the otdbuf^ kt- 
taii*|ihi^r«. Or tlnDitgh oijgca. IlA propfirtioD in the air is ni[i{nseil to be nuidi 
lncr<.-a»Lil in Bturmi which arc aocikmpanied b; clrftrif^ pfacBCUiMSiiL Scfafinbciu 
L'i|K<»o<l ajumdla to (lie KctioD of Ifais Bnbsteocc A do^ cOafimd fiw an boor ik 
■ li«ll>j;la8s, Uii4> which osoiie «u puacd, dtcid, ibougb it wms caliniatad tlial b* 
■liBiirlH>il uiilv abuui "US of b gnin. An (^Kamlnattou »haired die lungs in ■ auh 
iUli«ll uf Uf'lif* jnDiLrriiuMJon. H. 4^ b Biro, who bu alto «spaint«ql«l Vf^t 
h. ratiitn!- ■ nil ihp rvsj'imit'rr orafini lo thai of chlorine (Bnot^n^ 



coMPMirrow of the aih. 

Iialed, as fiist an tliey were pruducecl, dieil of aspTiprfa when 
the qimntitj- uf osygen became redaced to from 3 to 5 per 
cent.' 

Fnllowing Lavoisier, the Abbe SpiiUanzani,' by researches 
on a great numVierof aiiimuls of all (."hisseSj denioastrated the 
universal neccssirj of air, either in a gaseous condition or iu 
Bolntion in Hqukia, thvou«;^hout the animal kiugdom. 

A few experiments are on reeord in whitth the human 
Buhjeut and aniiiiala have been made to respire fur a tune 
pure oxji^eD. Though this is the gas which is ea&ential in 
ordlimry respiration, tlie procefes l)eiiig cairietl on ubout as 
WL^U in a mixture of oxygen ivith hydrogen as willi nitrogen, 
tise functions do not eeeru to he niudi altereil when the pure 
gas is taken into the lunga. Some authore state that ite pro- 
longed inhalation exaggeratea the functions for a time, and 
that iiiflammatiim of the hings and death fullow its pro- 
longed use ; while the experiments of others show that it 19 
hiinnlcss. T^voisier and S^^guin eoufined anininls for twenty- 
foar honrfl in an atmosphere of pure uxygen, without any 
notable results ; but, as is justly reniarlied by Louget, these 
experiments do not ehow that it wonld be possible to respire 
anmixod oxygen indefiuitcly without iuMnvenience.' As it 
esaeta in the air, oxygen is undoubtedly in tlie brat form for 
the permanent muintenantie of the respiratory function. 
The hlood seems to have a certain capaeity for the abeorp 
tion of oxygen, which is not increased when the pure g&s \& 
presented. 

The only other gas which ha$ the power of maintainiug 
re&piration, even for a thae, is nitroue oxide, This is ah- 
Burbed by the blood-corpnscIeB with great avidity, and for a 
time produces n.n exaggoratiun of the vital proeesses, with 
delirium, ete. — propcrtiea which have given it the common 



' BR^i.HP, ^p, riV., p. US', 

'' ^rALi.\M!A!(i, Mimoatt tur ta Rapiration^ tradaiU en Fmnpiii iTajirii mm 
maiiiucrU inid!.', 1S()3. 

• Ui.iflET, Traiti Je Pkijtioiofjie^ raris, 1368, tome i.. p. Ml» 



416 BESPIKATION. 

name of the " laughing gas " ; but this condition is followeJ 
by anDesthesia, and finally asphyxia, probably because the 
gas has such an affinity for the blood-coriiuscles as to re- 
main to a certain extent fixed, intertering with the inter- 
change of gases which is essential to life. Notwithstanding 
this, experimentere have confined rabbits and other animalf) 
in an atmospliere of nitrous oxide for a number of hours. 
In all cases they became asphyxiated, but in some instances 
were restored on being brouglit again into the atmosphere.' 

Other gases which may be introduced into the lungs 
either produce asphyxia, negatively, from the fact that tliey 
are not absorbed by the blood and are incapable of carrying 
on respiration, like hydrogen or nitrogen, or positively, by a 
poisonous efiect on the system. The most important of the 
gases which act as poisons are, carbonic oxide, sulphuretted 
hydrogen, and arseniuretted hydrogen. It is somewhat nn- 
certain whether carbonic acid exerts it« deleterious influence 
as a poison, or as merely taking the place of the oxygen in 
the blood-corpuscles. It is easily displaced firom the blood 
by oxygen, and tlierefore does not aeem to possess the prop- 
erties of a poison, like carbonic oxide, and some other gases, 
which become fixed in the blood, and are not readily dis- 
placed when fresh air is introduced into the lungs. 

Consumption of Oxygen. — The determination of the 
quantity of oxygen which is removed from the air by the 
process of respiration is a question of great physiological in- 
terest, and one which engaged largely the attention of La- 
voisier and those who have followed in his line of observa- 
tion. On this point there is an accumulated mass of 
observations which are comparatively unimportant, from the 
fact that they were made before the means of analysis of tlie 
gases were as perfect as they now are. Though many of the 
results obtained by the older experimenters are interesting 
and instnicttve, as showing the comparative quantities of 

> LONQBT, op. dl., Pftris, 1868, tome L, p. B48. 



OONSUMPTION OF OXYGEN. 417 

oxygen consumed under various pliysiological conditionSj tliey 
are not to be compared -with tlie more recent observations, 
particularly those of Regnault and Reiset, Valentin and Brun- 
ner, Dumas, Andral and Gavarret, Seharling, and Edward 
Smith, with regard to the absolute quantity of oxygen made 
use of in respiration. In the observations of Regnault and 
Reiset, the animal to be experimented upon was enclosed in 
a receiver filled with air, a measured quantity of oxygen 
was introduced as fast as it was consumed by respiration, and 
the carbonic acid was constantly i-enioved and ciirefiilly esti- 
mated. In most of the experiments, tlie eontinement did not 
appear to interferfe with the functions of the aninml, whidi 
ate and drank in the apparatus, and was in as good condition 
at the termination as at the beginning of the observation. 
This method is infinitely more accurate than that of simply 
causing an animal to breathe in a confined space, when tlie 
Bonsnmption of oxygen and accumulation of carbonic acid 
and other matters must interfere more or less with the proper 
perfonnance of the respiratory function. This is known as 
the direct method of investigating the changes in the air pro- 
duced by respiration. As employetl by lieguault and Reiset, 
it is only adapted to experiments on animals of small size. 
These give but an approxiniutive idea of the processes as they 
take place in the human subject, as it is natural to su]>pose 
that the relative quantities of gases consumed and produced 
in respiration vary in difierent ordei-s of animals.' 



' la Robin's JoHrnal dt rAtiatomie el tfc !a rhiii>iijf-iiii<\ July, ISiU, tomo i., 
p. 426, we find an analysis of reacorcbcs o» respiration by Dr. MaxPi'tti-nkofcr, in 
whidi the conditions fur accurate obscr^'aiiuiis oti lliu linniiin subject sci'in to l>e 
(blfilled. Dr. Pettcnkofcr ha.^ eon^trui'tcil a c;biiml>i''r large enougli (oiuliuit niiian, 
■nd allow perfect frooilom of motion, eating, sloqiiu!:, etc., into vtiicb air i^ con- 
■tantlj introduci>d in definite quantitr, an'] fi-um wliicli tlu' jiroilucts of rcsjiiruiion 
■re constantly removed ami estimated. An inL-ouiplcte ivne^ of oliservjtioiis ie 
paUulied, which has particular reftTfncc to the produtts of rospiraiion. Thus 
br thfl Bnbject of consumption of oxygen h.iH not l>een eoni^iiioreii. Kxtcniied ob- 
Mmtionf by Dr. Pettenkofer will unilonbtodly settle many disputed ijui-^^lions 
KgHdIng the chuges of the »ir in rei']>Iratiun, Thi^ method wa-t adapted to the 



418 BE8PIBATI017. 

The indirect method was first employed by BoassingauU, 
but was particularly directed to the exhalation of carbonic 
acid. This obeerver experimented cpon large animals, such 
as the horse or cow, in the following way : Having first care- 
fully regulated the diet, so that there was no change in weight 
during the experiments, he carefully weighed all that waa 
introduced as food and drink, and all that was discharged 
as urine and feces. The excess in the quantity introduced, 
over that discliarged in the way above mentioned, represents, 
necessarily, the amount lost by the skin and lungs. By a 
quantitative comparison of the elementary constituents of the 
food and excrements, tolerably accurate results were arrived 
at ; thougli it must be admitted that this method would be 
considered of little value, did the results not correspond pretty 
closely with those obtained by direct analysis.' 

Estimates of the absolute quantities of oxygen consumed, 
or of carbonic acid produced, which are based on analyses of 
the inspired aud expired air, calculations from the aver- 
age quantity of air changed with each respiratory act, and 
the average number of respirations per minute, are by no 
means as reliable as analyses showing the actual changes 
in the air, like those of Regnault and Reiset, provided the 
physiological conditions be fulfilled. "When there is so much 
multiplication and calculation, a very slight and perhaps 
unavoidable inaccuracy in the quantities consumed or pro- 
duced in a single respiration will make an immense error 
in the estimate for a day, or even an hour. 

Bearing all these sources of error in mind, from the ex- 
periments of Valentin and Brunner, Dumas, and others, a suf- 
ficiently acctirate ai>proximation of the i)roportion of oxygen 
consumed by the human subject may be formed. The air, 

human subject on a smaU scale in 1843, by Scborliug, but then wks no siTntigfr 
ment for estimating the quantity of oxygen famiBhcd (MitSE-EnwABDe, P/tgti- 
oloffie, tome ii., p. 49S, note.) 

' BorseiKOArLT, Mim-nrea d« Chimte AgrUole H de I^j/naloffit, roria, 1854, 
pp. 1-12. 



COSSCMPTIOS OF OXYOEN. 419 

wbich containB, when inspired, 20'81 parts of oxygen per 
100, is found on expiration to contain but about 16 parts 
per 100. In otber words, the vohirao of oxygen absorbed in 
the lungs is five i>er cent, or ^ of the volume of air in- 
spired.' 

It is interesting and useful to extend this estimate as far 
as possible to the quantity of oxygen absorbed in a definite 
time ; for the regulation of the supply of oxygen where many 
persons are assembled, as in public buildings, hospitals, 
etc., is a question of great practical importance. Assuming 
that the average respirations per minute are 18, and that 
with each act 20 cubic inches of air are changed, 15 cubic 
feet of oxygen are consumed in the twenty-four hours, which 
represent 300 cubic feet of pure air. This is the minimum 
quantity of air wliich is actually used, making no allowance 
tor the increase in tlie intensity of the respiratory processes, 
wbich is liable to occur from various causes. To meet alt the 
respiratory exigencies of the system, in hospitals, prisons, etc., 
it has been found necessary to allow at least 800 cubic feet 
of air for each person, imless the sitnation is such that the air 
is changed with unusual frequency ; for, beside the actual 
loss of oxygen in the respired air, constant emanations from 
both the pulmonary aud cutaneous surfaces are taking place, 
which should be removed. In some institutions as much as 
2,500 cubic feet of air is allowed to eacli person.' 

The quantity of oxygen consumed is subject to great 
variations, depending upon temi>erature, the condition of the 
digestive system, muscular activity, etc. The following con- 
closions, the results of the observations of Lavoisier and Se- 
guin, give at a glance the variations from the above-men- 
tioned causes : ' 

' Hilki-Edwariis, Phyx'uAogie, tome iL, p. 610. 

*Toi)B and BotruAN, Phst'ioiogintl Anatomy aiid Ph^ioloffi/ of ^fan, Phila- 
ddpMa, 1867, p. 728. 

■ Taken from Losorr, Traiii de Phyu'wlogie, Paris, 1868, lomc i., p. 676, 
Though the nbeolute quanlititrs obtained by Lavoisier and S6giiin arc not so rc- 
Uable u thoso ubtuned by lator obsen-ere, yet the accurate employmeiit of th« 



iSQ 



nESPIEATTON. 



"1. A man, hi repostf B.n<] fasti'vff, with an external teni- 
|)erature of 90° FaLr., coDfiiimea 1,4<>5 (.'uhic inches of oxygen 
per Iioui'. ^M 

" 3. A man, m repose a^^fmfimj, witli an external tein- 
peratnre of Si?** Fulir., consmiies 1,027 cubic incEies of oxj-geii ^ 
per littur. ^M 

"3. A man, thtrtng diijmtimi^ cuneiraee 2,300 cuhic" 
inches of oxygen per bour, 

" 4. A Tiian,/iM/Mi(/, while he accompJiehes the labor ne- 
cessary to raise, In fifteen niinutes, a weight of I'ZiZ kil. 
(about 111 lb. 3 oz. ar.) to the height of 656 feet, coosuiuea^ 
3,874 cubic inchea of oxygen per hour. ^H' 

"5. A man, (hirhig diffe^iion, accoDiplisliing the lalior" 
necessary to raise, in iiiteeu niinutefi, a weiglit of 7*3i3 kil. 
(about Ifl lb. 3 oz. av.) to the height of 700 feet, coiisuince 
E,56S cubic inches of oxygen per liour." 

Infuenco of TemperaiMve^ (?te.— All who have experi- 
mented on the inriiicuce of tciiiperatiu-e upon tlie oonenntp- 
tion of oxygen, in the warm- blooded anliuala and in the , 
homan subject^ have noted a marl?ed increase at low tcm-^| 
poratnres. Cold-blooded animals always sufier a depression ^1 
of the vital proceeds at low temperatures, with a corre- 
sponding diminution in tbe fjuantity of oxjgien coceuiti&lj 
until they fiuiilly become torjjid. 

Iiniuediately after birth, the consumption of oxygen io | 
tlie warm-blooded animals is relatively verj' elight. Buffon' , 
and Le>;allois* liave fihown that judt after birth, dogs and 1 
other animals will live for biilf liu liour or more under wattT; | 
and cases are on record where life has been restored in newly- | 
born ehildi-en after seven, and, it Ims been stated, after twenty- 
three Uoiira of asphyxia. During the tii-st periods of exibt- 
enee, the condition of the newly-bom approximates to that of aj 

best imans of iovtw ligation at their ciminiftnd leikda ua io pkce ertTy conKdeiMlj 
in the cumtjarivlive rL^iillB. 

^ 11ii.sk-Edw*iu«, rhi/xiohpit, tome ii.. p. BB*. 

< ljcuiL].ot^ Gi'uvrm, Pnria, 1»24, tome 1., p. M. 



INFLUliXCE OF TEMI'EKATUEE, ETO. 



421 



eold-!ilof>tled anniuil. Tlio lungs are relatively very sruall, ntui 
it is some time before they t'nlly assume thi?ir function. The 
mn^uJiit' raovenients are liardlj more than is necessary to take 
the etnaU amount of noiirishmeiit consulted at that period, and 
nearly all of the time is piisseU in sleep. There is also very 
little power of resistance to low tem]>emture. Though accu- 
rate reaearchea re^iinling tlie cotiiparativc quantities of oxy- 
gen in the venous and iirtorial blood of the fwtns are wanting-, 
it has been frefiuently observed that the differcTice in cfllor is 
not as marked fia it is alter pulmonary res-pirntiiin becomes 
ostablished. The direct researches of W. F. Edwards Iiave 
shown that the absolute cnneumption of oxygen by very 
young animals is very small ; ' and the obeervationa of LcgaU 
loia nn rabhitB, made everv live days during the tirgt mouth 
of exist.pnee, show a rapidly iuereaBiug demand for t-his prin- 
ciple with ago.' 

RegTiault and Reiset hare Bbown tliat the coneumption 
of oiygen is greater in lejin than in rery fjit atiimals, prL>- 
vided they be in perfeet health. They have fd^ shown thut 
the con«iumption ie much greiiter in enrnivorous than in 
herbivorous animals ; and in aniniala of difl'erent sizes, ia 
relatively very much greater in thoBe which are very gmall. 
In very small hirdB, Buuh m the sparrow, the proportional 
rjuaniity of oxygeu alworlhed waa ten times greater than in 
the fowl.' 

In sleep, the quantity of oxygen consnmed is eonaiderably 

' Ih riiijdtrnct iltt Affent PAifiyua tur !a Vie, Fmrin, 1SS4, p. 17B tl **g. 

' Loc. fir. Id lii* especiniL'Qtti on rabWta, I.epilloi» fonml ilmt iiumraediantly 
ftfter Vmh tbcy troiilJ live for Sifleca miauled du-privctl of air. '^ In » pity sis liug 
nbliits of ditTGrcDl agw, for enftajple, evury Stc Jaya, froTii tlin; momuBl ai binJi 
lo t^ieage of one inonTh, it naa cnnetnnlly obacired thnt tlie durnlion of sensa- 
tion, of Toliintury [uoLion, in a word, Ihe signs of lifr, alirayH ditnlnialicil in pro- 
(MTtlaii as ilie animolD udvaiiced in 1^. .Thus, in a rabbit ocirlj bora, BenBaUon 
Kid Toliintan' mnveiiicDU irera Qat extinct until Lbe end. or about fiEWnD minutvi 
of uqjhvxiii, irhilc tbcj were eitinci in k«j (ban two mmutcs in a rabbit of iba 
tgt yf Ihirtv ilajs," p[\ 57, 68. 




BESPntATlON. 



Jimiiiislied ; and in liibemation is bo email, t1iat Spallnnzani 
uoiiW not detect any rliflerence in tttc fimiipisition of tlio «ir 
ill wliicli a marmot, ui a slate of tor|tor, liad rciinune<i for 
three liniirs.' In exporimeiUs on a marmot in liibL-niation, 
Rt-gimult and Reiset observed a rwJoctioti iti tlie ciuanlity of 
oxygen consuiiiGd to about jV <■''* ''^^ norma! stiunlard.* 

It lias been slionn Uy ex[ieriiaenta, tliut the con&uin|>tion 
of oxygen bears a pretty eoLstant ratio to tlio prirtluelion of 
carboiiit; ueid; and as tlie ubfiLTvatione on tlie inflwonce of 
sex, nunihtT of respiratory acts, etc. on the actinty of tite 
reepiratory processeB, liave been made chiefly wiili reference 
to the earbortic acid exhaled, we ahflll consider these in- 
tiiicuce^ ill Cfiitiectioii with the products of respiMtioii. 

Experiments on the effect of increasing the proportioD of 
osygen in tlie air have led to varied ro^ults in the ]iaiid« of 
ditierent observers. Regnault and Reflet, wlnj^e olMerva- 
tions on tbia point are generaJIy accepted, did not discover 
any ircreafic In the conanmption of osygen wlieti this gas wue 
largely in exect^s. 

The results of confining an animal in an atmosphere com- 
posed of 21 parts of osyi^cn and 70 parts of hydiiigvn are 
very curious and iiibtructivo. When hytlrogen i* thus snb- 
atituted fur the nitrogen of the air, the cunsnmption of oxrgeti 
14 largely incix'flsed. Regtiault and R^iscl atrribtite this to 
the superior refrigerating power of the hydrogen; but u more 
rational explanation -Nvould seem to be in itjs eupenor diffusi- 
bility. Hydrogen is the most diffueible fif all gaaee; and 
when introduced into the luiips in the place of the nitrv^cn 
of tlie air, tlie vitiated air, chiirged with carlK>nie acid, is 
undonhtedly moro rondily removed from the deep portions 
of tiie lungs, giving phu-e to the mixture uf liydrogeo and 
oxygen ; and it is probably for this reason that ilie quantity 
of oxygen consumed is increased. It is probable that the 

' SFjLUU^s^tatt Jfmoirr* *ur la Jitmpinttttm, tradiUla par StifmjB, GcDi'irv^ 
leos. p. 3a4. 

• Op. ril., p. iHp. 




IKFLUESCE OF TiMPEEATUEE, ETC. 42S 

nitrogeu of the air plajean important part in the phenomena 
of respiratioa by virtue of its degree of diffosibility. 

In Tiew of the great variations in the consumption of 
oxygen dependent on different i)hysiological conditions, such 
as digestion, exercise, temperature, etc., it is impossible to tix 
upon any namber which will represent, even approximatively, 
the* average quantity consumed per hour. The estimate 
arrived at by Longet,' from a comparison of the results ob- 
tained by different reliable observers, is perhaps as near the 
tmth as possible. This estimate puts the hourly consumption 
at from 1,220 to 1,525 cubic inches, " in an adult male, during 
repose and in normal conditions of health and temperature." 

In passing tlirough the lungs, the air, beside losing a 
proportion of its oxygen, undergoes the following changes : 

1. Increase in temperature. 

2. Gain of carbonic acid. 

3. Gain of watery vapor. 

4. Gain of ammonia. 

5. Gain of a small quantity of organic matter. 

6. Gain, and occasionally loss, of nitrogen. 

The elevation in temperature of the air which has passed 
through the lungs has been carefully observed by Dr. Gre- 
hant.' He found that with an extenial temperature of 72°, 
respiring 17 times per minute, the air taken in by the nares 
and expired by the mouth, through an apparatus containing 
a thermometer carefully protected from extenial influences, 
marked a temperature of !)5-4°. Taking in the air by the 
mouth, the temperature of the expired air was 93"*. At tlie 
commencement of the expiration, Dr. GreUant noted a tem- 
perature of 91°. After a prolonged expiration, the temper- 
ature was 9Q°. In these observations the temperature taken 
beneath the tongue was 98°. 

' Op. at., p. S31. 

• Gk£ii.i!IT, ReeKereha Phtfuiqvea wnr la Itfipiraiion de VHonune. — Journal ilt 
FAnaiomU etiUla Pkgtiologie, 1884, tome i, p. 646. 



4S4 



BEBFtKATIOK'. 



Valentin had pi-cTicu&ty made expenmeiits ou t\n 
ami put tlie tcrnperatun^ ot" the ex]jired air a little liigher; 
viz., about 99", witb an external teen perat are of 68". He 
u1bi> slioweil tliat tlio teinprrature of tlie siiiToiinding atiiios- 
pliero exoi'ted im important influeittre on t!ie tcm^TKliirt of 
the expired air. In an obserration made in winter, witb an 
external tenipL^rature of 1S% the temperature of tbe espji 
air \\a« only 85'&°.' 

Kefialation of Oafbonie Acid. — The produL'tion of car-^ 
bonic acid in tiie respiratory pro(*93 is as universal as the 
consumption of oxygen. Experiiiienta have shown that all 
animals dnrinff life exhale this principle, aa well as all tis- 
siipfi, so long aa they retain their irritability. This takes 
plate, nut only wtien the aJiimale or tissues are placed iu mi 
atmos]iliere of oxygen or common air, hut, as iv*as obacrfed 
hy Spalliinzaiii," in an atinosphece of pure nitrogen or hydro- 
gen. Tiiia tact bas since been noted by W, 1'". Edwards, J, 
Miiller, G. Liebi^', and others. 

The study of the exliiibition of carbonic acid preseuta eei 
era! priihloma of great pbysioloj^iral interest: 

1. What is tbe absolute quantity of carbonic acid ex:hal< 
by tbe Imigs in a given time i 

2. What are the variations in the exhalation of tbia prin- 
ciple duo to ])!iyiiio!ogical influences? 

3. What is the retation hcitiveen the quantity of carboniflj 
acid produced and the quantity of oxygen consumed 7 ^H 

On necourit of the variations iu the tpmiititiea of earbonic 
acid exhaled at difl'erent pcrioda. of the day, and particularly 
the great influence of the rapidity of the respiratory move- 
lueutis, it is exceedingly difficult to fix upon any nunilMT 
which will rejiroficnt tbe average proportion of this gas, con^^ 
tained in the expired air. The same influences were foun4^| 
nftecting the consumption of oxygeu ; and tbe aarae difficulties ' 

' l<KKiiA,vr, lirrhrri-hn I'/iiftujue* nvr la /Uafiiralian li* rj9(»n<H«,— .^iwW i 
r^natu/iit* ttJtla Phytuiiiiji*, 1SD4, locii« L, p. S45. 



EXHAIJ.TION OF CABBOSIO ACID. 



422 



were oxperipnced in forming an ostitnjkte of the proportion 
of this gas consumed. A3 vre assumed, after a traniparisoc 
of the resnitg obtained by dilferent observer, that, the vo!- 
rnne of oxygen coneiimed is about five per cent, of the entire 
vohime of air,, it niaj be ptated as an Approximation, that in 
the intervals of dligee.t,ion, in repose, Rud under normal ron' 
ditious aa regards the frequeripy of the pulse and reepiration, 
the volnrae of carbonic acid exhalef! Is aimut ftnir per cent. 
oFtht! volume of the expired air,' As the volume of (he oxy- 
gen which enters into the eonipositiou of a defitiiio cjHantity of 
carbonic acid ia precisaly equal to the volume of the car- 
bonic acid, it is seen that a certain quantity of oxygen disap- 
pears in respiration, and is not repr^iented in the carbonic 
Acdd. exhaled. 

Tlierc! are great differences in the proportion of carbonic 
acid in the expired air, depending; upon the time during 
which the air has remained in the Inn^. This interestina 
point hfts been studied by Vierordt, in a series of 94 experi- 
menta made upon his own person, with the following results : * 

"When the respirations nre frequent, the riuantity of car- 
bonic aeid expelled at each expiration ia much Icm than iu a 
alow expiration ; but the quantity of carbonic acid produced 
during a given time by fi-eqiient respirations is greater than 
that wliieh is thrown off by slow esjii rat long." ' 

The flir which escapes during tTie tirst period of an expi- 
ration is naturally less rich In carbonic acid than that which 
is IhsI expelled and couies directly from the deeper portiona 
of th'S lungs. Dividing, as nearly as possible, the expiration 
into two equal pail^, Vierordt found, as the mean of twcnty- 

* HiLKE'EDTTARiia. Phuniilaffie, lome ii,, p. SOT. Tbia approtdmaiLati h takoo 
Aomtbc (ib>-erTiitions of Vdk'titiu unci BmuDiT, Datlon, Prout, Ap^oliD, Cn^lhupe, 
Hgm. anil Viurorilt. The ciperliuciiU vf Vu'rorilt iire, perbaps, cnlitlod to the 

tnmt cnNlii, ns hn Las siuitk-iL vury giLre)'iill; the- ijiflu^sQce- of tbe froquEinc^ orrw. 
yiratluii n]yia t\i« quiLTititf of cu'lvoiitt' itcid t'skikcl. 

* Cilfsl in M I Lvt-l!^Dw.i RDB, rAifnoh^iA, tome a., p. ili, and Bkuaihi, (X>un 
dt PAytiolryjie, Ionic: iU,, p. S49. 

* filAAHD, ior. eH. 



426 RESPmATION. 

one exporiineiit?., a ]>eroeiitnge of 3'73 in the first part of tl 
expiration, and li'H in the stsfond part,' 

Tpmporary nrrest of tlie refpii-atury nioTenients, as 
slionld expect, lias a marked influence in increasing tW pj 
portion afeavlmnit! acid in tljo expired air; thougli the nbso- 
lutc qnnntity exiialed in a given time is diminished. In 
iinnibcr of exjjerimenta on his own perfeon, Vierordt a&c* 
tiiined tliiit the pertentiige of cJirTjouip add lieeomw unifiw 
m all piiild of tlie respirntory organs, after Jiolding the 
breath fur 40 seconds. Etolding the breath aft^r an ordinitry 
inspiration for '20 seconds, the percentagt; of carbonic acid 
in the expired air was increased 1*73 over the norniftl staiit 
ju'd; but the ahaplnte quantity ejchaled waa dimlni^he<i bi 
2'G42 cubic incliee. Alter taking the deepest pi;»ssib]e inspi 
ration, and holding the breath for 100 Beuondi;, the percent 
age was increased 3'OS above the nnminl Btaiidard; liut tlio" 
absolute qimutity was diminished more tiian 14 cubic inchts.' 
Allen and Pepya state that air which has passed 9 or 10 tim« 
through the hings contains 9"5 per cent, af carbonic arid.' 

Vierordt gives the ibllowing (brmula as represouting the 
influence of the frequency of the respirations on the prodiM 
tion of carbonic acid ; T:Jving 2'5 parts per hundred as rep 
resenting the conetant vahie of the gas exlmled by the blood, 
the increa&e over this proportion in the expired air is il 
exact ratio to tlie duration in the contact of the air anc 
blood. This, though it may hold good iu many in&tauc 
Beenia rather an excessive refinetneut.* 

' IxBJiisv, Phi/aiol-'ffifal ChemUttg, Philad<?lpliiii, 18153, vol. H., p. 489. 
' Vj/fiopadlii a/ Anatomy aiui Fhjjiidaffy, unl. tv., part 1, p. &6% 

* HiiiL 

* The fciiloiriDg table ff-iea at a gl&n«c tfa« moat important resulU of 
eipurlmuulfi ; 

a-T |»f IW puT* (if •!», , ,.,.... « 

4-1 " " - ., » 

$-a " " " u 

H - • " ,, u 

M - " » .. H 



OK CAKBONia ACID. 



4S7 



Tlie abaoUitw qiiaatitj oJ'caTbotiic acid exhaled in a given 
time is a more iiiiportnut subject of inquiry tlian tlie pTOpor- 
tion eoutalued iu the t-xpii'ed air ; fur the latter ie coustant- 
ly varying with every moditiGiitiou in the number and ex- 
tent of the respimtoiT acts, aud tlie vulume of brentbin^ 
air is subject to gresit fluetuationB, and is \evy difficult of 
deterrainarion. The direct metliodj in which the actual 
products of respiration are collected aud estimated, has led 
to vei-y IiujKirtJiiit r&sulls, whicli have l>een contirmed to a 
certain extent by BoaselngauU, Curral, and cthcra who Iiave 
employed the indirect uiotliod. It is by the direct niethod, 
in the hauiLs of Kegiiault and Reiset, Aiidral and Gavarret, 
and more recently Dr. Edward Smith, that we have learned 
BO much rep;arduig t!io pliysiohigi<'al varititionA in the prud- 
ucta of re3piralion ; one of the most important cnnsiderationa 
connected with the sabjeet. 

AuioTig the most reliable obaervationa on the qnantity of 
carbonic acid exhaled by the human suhjci2t in a definite 
time, and the variatiom to which it is subject, are thoee of 
Andral and Gnvarret,' and Dr, Edward Smith." Tlie obser- 
vations of Lavoisier and Seguiuj Front, Davy, Dumas, Allen 
and Pepys, Schailijig, and utliere, Lave none of them seemed 
to fulfil tlie necessary experimental conditions so cnui]iletely. 
Scharllng'fl method was lo enclose hie subject in a tight box, 
with a capacity of about 2" cubic feet, to which air waa con- 
stantly supplied; but the observationa were comparAtively 
few, being made on oidy six jiersons. In his ol>servatIons, 
the quantities of gne exhaled must have been considerably 
modified by the elevation of temperature and cxhalati(.>n of 
moisture iu so Btuall a epaee.* The mental couditiun of the 

' Rtflt^rchrt mr la QuaniUi tfAti'U C'lrhoniyu^ ahafr par It Fi.'wni}ni dani 
PApia Ilutiutirif. — Annt'leiife Cli'imit r{ de J'ftifii'^ut, 3mBB6rie, tonus viii., p, 120, 

* ElfiVAilu Smitii, Ej:pfri/iirntal Iji'fwiricK tain (Af Chemiral aiirf other Phtni/m- 
Tjia nf /7rii/Mi'ali'ni, ami Ikiif AfotJiJirutioiui (iff vnriimn Fkiftica! JyrriWi* ( J'Afc 
iatirpliifjil T-unn'jrlUiris, l^i^9, p. 681); nnJ On tht Aftiwi of FninJ/ upttn Uu 
Rrapiralvtn darintf iltn Primarif Prneata of Digmtion (Ilihf., p, TIS). 

■ Annalm lU Ch'">. ■et lU Phi/r^ tome Tiii., p, 488, Schftriing pocognized ibt 



4SS 



RESITHATION. 



eubject of an experiment has an iDHiienco upon tlje prodncts 
of respiration, iiud the fmitttou ie soiDetimes iniMlitiec! from 
tlie mere fact tUat an experiment is being performed; an in- 
fluence wiiieli Scliarling did nut fail to recognize, but whiclt 
frequently cannot be guarrJeJ ngainet. 

Tlie observations of jVndral and Gavarret were made on 
aixty-two pereons of both eeses and difl'erent apes, and uhcIlt 
absolutely identical conditions us rcgarda digestion, time of I 
the day, barometric presaure, and temperuture. Tlie prod- 
ucts of respiration were eoUected in the following way : 
A thin mask of coppf3r covering tlie face, and large enongli 
to contain, an entire expiration, was fitted to tlie la(-'« by . 
its edgesj which were provided with India-rubber, 8o as to^| 
make it air-tight. At the upper part was a plate of glass for ^1 
the admission of light, and at the lower jiart an o|>efung, 
which allowed the entrance of air, but was provided with a 
Tulv© preventing its escape. By another opening the tua&k 
was connected by a rubber tube with three glass ballooua, ca- 
pable of holding S,544 <iubic inchee, ia which a vacuum was 
previonsly establiehe^b With the nia.sk fixed npun the face, 
and a stop-eoek opened, connected with the bialloone, so as to 
graduate the current of air, the subject re&pires treely in the 
current \i'hic;h coniea from the exterior into the receivers. In 
this way, though the qnantity of air respired is not measured, 
the vacnum in the receivers draws in the prodncte of respira- 
tion. The current will continue for from 8 to 13 minutes, 
and is bo regulated that the air is respired but once. The 
quantity of caxbonie acid in the receivers represents the 
quantity produced during the time that the experiment has 
been going on. 

By carertdly fultiEIing all the phyaiologiea! conditions, 



newssilj «f guarding Against the iaflui^iic^e -or elmtion of U-tnpi.-nituni' aad kv» 
niululioii vf uoUmri.% and ntteraptod lo ri?iuov« the InKtr b; uitmducing k rontl 
of eulplmriu aoM, Bin groatcHi dI^L''uh}' wiu in tlit< uoalvi^'eB of ilic Air. Tkongib 
ttic re^alta ubciunQtt axv vduablc-, ib-e process cannot cLaun Ok Bccuncj Aiuioed 
b^ Andr&l and GuTairei. 



EXHALATION OF CABBONIC ACID. 



-ISO 



rcgiilating flie number of respirations, as fur as possible, tn 
tlie nuniial Btandflrd, difiet'ent obscrrations on the satne sub- 
ject, at diffHjrent times, under tbe Bsme conditions, were at- 
ti'nrled with results so nearly ideuticnl, as to give every con- 
tidcQce iu the accura^j of the proreas. But even tlieu, these 
Lfhservere recognized sueli iiumenfie variatlona in the exhala- 
tion of carbonic acid with the coustantlj varying phj&iologi' 
cal t'onditions, that they did not feel justified in taking their 
lihserTations as the basis for caleulatious of the entire quantity 
exhaled in the twenty-four hours, 

Tlie reaolts of these obeervutions on the male, between the 
ages of" frixteen and thirty^ between 1 and 2 p.m., under iden- 
tiuil couditlone of tho digestive and muscular systems, eauh 
exjierimeiit histing from eight to thirteen niiTintoe, showed on 
exiiahition of about 1,'220 cubic inches of carbonic acid per 
hour, 

Dr, Edward Smith,' in his elaborate paper on the phe- 
nomena of respiration, employed a Y^ty rigorous method for 
the estimation of the carbonic acid exhaled. He used a 
loafik, tittinp; cloaely to the f;ice, wlucll covered only the air- 
pabBages. The air was admitted after being measured by 
paesiuj; through au ordinary dry n;ne-nieter. The expired 
air wai5 passed through a drying apparatna, and the carbonie 
acid absuibed by a solution of potash, arranged in a Dumber 
of layers, so ae to present a surface of about TOO square inches, 
and carefully weighed. This apparatus wag capable of col- 
lecting all the carbonie acid eshaled in an hour. The esli- 
tnate was nsado lor 1§ waking hours and 6 houi-a of Bleep. 
Tho obaervatlons for the 13 hours were made on four persona, 
namely: Dr, Smitfi, a^t, 3S yeai-s, weigliing 190 pounile, *! 
feet high, with a vital capacity of '2SQ cubic inched; Mr. 
Muni, ret. -18 yeare, 5 feet 9J inches high, 175 pounds 
weight ; Dr. Mune, ret. 2G years, 5 feet 7J inches high, 133 
pounds weight, vital capacity 250 cubic inches ; Profl Frank- 
iandj ffit. 33 years, 5 feet lOJ inches high, and 130 puuada 




430 



EESPmATION, 



weight. Breakfasf was taken at SJ a.m., dinner at li^ tea at 
5i, and &Lipper at 8^ f .al TLe ubservations oci-npietl ten inin- 
utes, and were made every Iiour and half-bonr ibr IS lioure. 
The fivenige for the 18 Lours pive 20,082 rcibic inrht's of 
carbonic acid fur the whole jjei'iod. Observations diiriof^ the 
6 houra of sleep showed a total exhalation of 4,12*3 cubic 
inches. Thia, added to the qnantitj exhaled dm-ing the day, 
gives as the total exhalation in the twenty -four biiars,<fMr»Mj? 
coifipl^U repose, 34,208 cubic inches (about 14-24 cubic feet), 
containing 7'144 oz. av. of carbon.' 

Considering the great variations ia the exlialation of car- 
bonic; acid, this estimate can be nothing more than an ap- 
])ro?dniation. One ol' the great modifying influences is mus- 
cular exertion, by which the production of earbonie acid is 
hu'gely increased. This would indicate a larger quantity 
during oniinary conditions of exercise, and ft maeh larger 
quantity in the laboring elapses. Dr. Smith givea the fol- 
luwiog npin*o?;Imate estimates of these ditfurence* : ' 

Id quicCaJe . 7'H4 oe. bv. of carbon, 

Nun-Ubonaus daw BCa " " 

Uborio«9cl»9s IIT " " 

In studying the variations in the exhalation of carlM>tuc 
acid, important intbrmaticiti ha^s been derived from ejcperi- 
meuls by many observerB on the inferior animals, ae well an 
from the observations of Duinas, Prout, Scliajliog^ and others 
on the human fiubjecL The principal condiliooa which 
influence the exhalation of this principle are : 

Age and sex ; activity or re[)<:i3e of the digestive s^'stem ; 
tbrm of diet; sleep; muscular activity; fatigue; moisture, 
and surrounding temperature ; sea8<on of the year. 



■ (}p, n(, p. ft9i. Iq these nlcukttoiu tben u ■ »lif^t MidUDfiin] emr; 
but it mkk<^ ■ difibvnec at oulr to ruble iochea of ps^ in tbe «Hiiii*U far Um &t 
hoiu^ liL thti origiaal pftper, Ibe quuuii;^ b gijca br wdghL Wc hMa r* 
duix-ditlo cubk iDcheHf UBoauogtliu 100 «ituciiich«i of gu weigh 4tMg]rria« 

■ <^>. dJL, p. 1193. 



fLXrESCTl OF AOE. 431 

Tnjiaence of Age, — In treating of the coHsumptiou of 
oivgen, it was stated that daring the firet few tlaja of extra- 
uterine existence, the demaRd for oxygen on the part of tlie 
system is very slight. At thia period tliero ia a correspond- 
ingly feeble exhalation of carbonic acid. It is wull known 
that during the first hours Hnd days after birth the new 
being haa little power of generating heat,, needs constant 
protection from changes in tenipeiature, and thu volun- 
tafy niovemente are very imperfect. During the tirst tew 
days, indeed, the infant does little more tliau sleep and take 
the email qnaotity of colofitriiin which is liimishefl by the 
mtiramary ghitida of the uiotliGi*. While the animal fmictions 
are so iraperffectly developed, and until the nouriehuient he- 
come« more ahnndant iiiid the chihl begins to increase rapidly 
in weight, the quantity of carbonic acid exlittled 13 veryamall. 

After the respiratory function beeomea fully established, 
it is probable, from the gi'eater niimbor of respiratory move- 
■meuta in early life, that the pivduction of carbonic aeid, in 
prupoi-tttin to the weight of the hody, is greater in infancy 
than in adult life. Direct obs^rTatiuns, however, are wanting 
on tliiti jxtint. 

The obaervations of Andral and Gavarret ' show the com- 
parativt! exhalation cif carbonic ntnd in the male, from the age 
of twelve to eighty-two, and give the results of a single obser- 
vation at the age of one hundred and two years. They show 
an increase in the absolute quantity exhaled fruin the age of 
twelve to thirty-two; a slight diiuinution from thirty-two to 
eixty; and a considerable diniiiuition froru sixty to eighty- 
two. These reeiilts are given in the fuUowiug table: 

Cm 'hntJc ac^ nrAti Ifl ptr /tour. 

In bop from tweire in stitci^ ^cuni VI 9 culiic invlie^ 

Inyoimgiupu TroTO aevrowcn to nintlsen yeare. 1,280 " *• 

la incfi troui iweciy-fivc to i4iirly-tw« years. 1,343 " ** 

In men. from tliirty-twu to sixty ypura l,2iU " '* 

In mea from eiiry.tbree to ci«bty4wo yuirs 83a " '* 

In ta -Did ntui Qf va^ liunilrQil iinJ two yonra, ,,,, A71 " ** 

'LoceU. 



133 



EP3PmJLT10S. 



Talking into consideration tlie increase in tlie weight of 
tlio hoi]y ivitb age, it is evident that the R'spiratorv aeli^-ity 
is much greater in youth than in adult life. Andral and 
Gavarret do not give tlie weight of t!ic eubjaits of their 
obaervalioDSj bat aa the weight generally does not dimimsh 
after Tuaturity, there ean be no douht tliut there is a rapid 
diminution in the relative quantity of carbonic acid produced 
in oTd a^e. 

Schai'ling, in a Beries of observations on a toj nine yeara 
of age, weighing 48 5 pounds, an adult of twenty-eight, and 
one of thirty-five years, the latter weighing 1G3-6 pounds, 
showed that the respiratory activity in the child was nearly 
twice as great, in proportion to his weight, aa the average in 
the adults.' It is seen f™m the observations of Audral anj 
fiavarret, that the absolute increase in the exhalation of car^ 
bonic acid from cliilJhood to adidt life is very slight in com- 
parison with the natural incrense in the weight of the body ; 
fthoiving that, proportion ately, the exhalatiou of earI>ouie acid 
iH greater in early life. 

T/t^iienm of Sex. — All obeervers have found a marked 
difference between the Bexes, in favor of the male, lu the 
proportion of carbonic aeid exhaled. Andral aud Gavarret 
noted an absolute ditiVrence of about forty-(5ve cubic inches 
per hoar, but did not take into consideration the ditferenoe 
iu the weight oCtho body. Seharling, taking the pmportton 
exhaled to the weight of the body, noted a marked ditferenco 
iu favor of the male. 

The ditference in the degree of muscular activity iu tlio 
sexea is sufficient to account for the greater evolution of ciir^ 
bonic acid in the male, for this principle is exhaled in pro- 



' ScnjiRLiva, Recherefiamrla QiMollti d''AciJe Caritniqut npirijMr rHammt. 
AnnaFn de Cfiimit rt da J'fii/mipif, Sine iSri«, tomo vili,, p. 4B*. 

Tt)kiDg tlio proponion oi carbouic acid csbaled pur Tipor U» the "eiiHit, In 
it\e mail i& fiacs of &ge, lu 1, in Ciio miin S.^ years of ngc tlie praportioa wns L*l-l| 
KtidLnihelKiy ff};ejin ofago, 2-07. F. 469. 



t-UENOB as mOESTION. 



433 



porllon to the musculiii: development of tlio inflivitlnal ; but 
thore IS iin important cliflereiiee comiected 'snth the variutione 
witUagE?, whieli depends upou tlie cunditionof tbe genei'jttive 
system of llie I'euiale. 

Tlie absolute innreaae In the evolution of carbonic acid 
with age in tbo t'emsile is nrrested at tlie time of puberty, 
aud remains atntionary during tbe entire menstrual period, 
provided the nien3trnftl How ooenr with i-ogularity. During 
tbis time, the average oxlmlatioii pea* lioiir m Tli oubic IntbeB. 
After tbe eessation of the menses, tbe quantity gradually 
increases, until at tbe 111,^0 of &Iit j it amounts to 915 cubic 
iuubes per lunir. From the ago of sixty to eigbty-two, tbe 
quantity dtmimsbcs to 793, and iinally to 670 cubic iucbos. 

AV!ieu the meuBPs are suppressed, there is au increase in 
the exhalation of earbonic acid, wlucli continues nntil the flow 
becomes reestablished. In a ease of pregnaney tbe exhalation 
■was iucreafied to about 88a cubic inches.' 

Tnjiu^nc€ of Digestion. — Almost fill observers agree that 
the exhalation of carbonic; atud is increased during digestion. 
Lavoisier and Seguin found thiit in repose and fasting, tbe 
quantity eshided per hour waa 1,210 cubic inches ; ivbicb n-as 
raised to 1,800 tuid lj9i_»0 during di^'eBtion.' Numerous ex- 
periinentaon animals have coutirmed tbiistateinent. A very 
intcrest^ing series of observnlioii3 on thia point was made by 
Tiei'i-'rilt upon, bis owti person. Tjilcing bid dinner at from 
12'30 t:> 1 r. M,, having noted the fret]uenc-y of tbo pulse 
and respirations and the exhalation of carbonic acid at 12, 
he found at 2 r. u. the pulse and reepiratioua increased in 
frequency, tbe rolume of expired air augmented, and that 
the carbonic acid exhaled bad increased trom 15-77 to 18-32 
cubic inches per minute. In order to ascertain that this 



'ThBAbove (acts, showing the peculiar Influence of the coudltioa of die getfi'ni- 
tive oi^iuis in the ff male, are eiiiioq^ the most impoctaDt KSuJta of the ubsi^rvt- 
tiooft of Andnl and Gururrct, Lot. tH, 

* Cj/doptailia of Aiutiomyand ^K*falolog^^y6L iT., part L^ pp. 34fl, 317. 



434 



RESPEKA.T10N. 



rariation did not depend upon the time of day, indo- 
[lOiideTidy of" tlie digestive process, he made n compamim at 
13 M.t flt 1 and at 9 p, m., whhout taking food, which showed 
no notable vaHstion, either iu the pulBe, number of resptra- 
tioiis, volume of expired air, or quantity of carbonic acid 
exhaled.' 

It is ^Ulneces3n^y to cite other observations on this point, 
unless "we mention tliose of Pront and Coathufie, which 
Beeined to show a diminution in the exlialation of L-arbonio 
add during digoetion. Dr. John Keid, in the Cydoptttfia 
of Asiiitowy (ijnf Phijsto}<)gy^ points out the sonrco of error 
ill t.]iO(4o obscrvalLoiis.' Pruiit did not estimate tlie actual 
quantity of gae exhaled, but only its proportion in the ex- 
pired air; and it ha^ been demonstrated that in digcetiou tbo 
volume uf the expirations is notably increased, Coaihape, 
in the uhservatioua on his own person, took a pint of wine 
with hi= dinner. As it has been shown by experiment that 
alcohol has the effect of rapidly- reducing the eilialatiou of 
carbonic acid, this observation does not represent the ample 
influence of digestion. 

There can be no doubt, then, that the exhalation of car- 
bonic actd is notably increai^ed during the functioBal activity 
of the digestive gy&teni. 

The otl;ect of inanition is to gradually diniiuislt the exha- 
lation uf carbonic acid. Thia fact was long since deinoa- 
straltid by Spallanzaui on caterpillars, and March&nd on 
fn>gs; but ohservationa on the wanu-blooded animals are 
more applicable to the human subject. Bidder and Schmidt 
noted the daily production of carbonic acid in a cat which 
was subjected to eighteen days of inanition, at tho end of 
which time it died. The quantity diminjahed gradvinUy ikiitt 
day to day, nutil just before death it was reduced a littla 
more than oue-lialC Dr. Smith* noted in his, own person 



* Op. d:., p. i«i. 



ISFLUENCE OF DIET,, 



435 



clie influence of a fast of twenty -seven leuurs. There was a 
niurkt-J iJiininution in tlie .fj^uflntity of air reajjired, in the 
quantity of vapor exhaletl, in tlie number of rcBijirationa, ami 
ill the rapidity of tlie pulfie. T/ifi ^xhahitionrtf carhiyni<; acid 
wtw diminkhtid o/iry/hwi/i. An interesting point in this 
observation waa the fact that tlie quantity was as sniall four 
and a liiih" hours after uuting, as at the end of the tweiity- 
eeveii hours. " An increase of carhonic acid in the absence 
of food, at or near the period when it is usually increased by 
tbod," was also noted in the experiment of Dr. Smith. 

Influence of Diet — Regnault and Reiset, in their espori- 
ments on animals, etudiud the effect of different kinds of diet 
upon the relatione of the quantity of oxygeu absorbed to the 
carbonic acid exhaled. About the only coiiclueivB and ex- 
tended series of invesrigations on the influence of diet upon 
the absolute quantity of carbonic acid exhaled are those 
of Dr. Smith. This observer made a large number of 
esperiinents on the influence of various lvin<k of food, and 
extended his inquiries into the influence of certain beverages, 
Bucb as tea, coffecj couoa, malt and lermented liquors.' "We 
have already fully described the method employed iu these 
esperiuients, and the eoiiclueions, whifb are of gi'eat interest 
and importance, arc very exact amj reliable. 

Dr. Smith divides food into two classes, one ■which in- 
creasw the exhalation of carbonic acid, which he calls respi- 
TUiffT'j excit^nU, and the other, wliich dim.inislics the exhala- 
tion, which ho calls nffii-eieciiers. 

The following are the resultaof a lai^e number of care- 
fully eondncted observations upon four persons: 

"The excito-respiratory are nitrogeneous Ibod, lullk and 
ita coinponeuta, sugars, rum, beer, atout^ the cereals, and 
potato. 

"The non-esciters areBtarch, fat, certain alcoholic com' 

' On Vu Afiitm of Foadti on At Ra^rufhit ilunng the Primary Procawn 



i3Q 



REePIEATIUN. 



pounds, the volatile elements of wines »nd spirits, arti] coffeo 
leaves. 

** Respiratory excitants liave a temporary action ; Imt. the 
action of most of them cninmeiices very quickly, and attaitu 
ita masimum witbiu one hour, 

"The mcKt powerful respiratory excitaats are tea and 
sugar; then coffee, rniir, milk, uocoa, ales, and cLieory ; then 
casein and gluten, and lastly, ^flatin and alhumeii. The 
amount of action was not in uniform proportion to their 
quantity. Com|ioiim3 SLilments, aa the (.cereals, containin«; 
several of these anitstances, have an action greater than that 
of any of their elemcnta. 

"Most respiratory excitants, as tea, coffee, gluten, and 
casein, causo au increase in the evolution of carlion greater 
than the quantity which tliey supply, "whilst others, as. sugar, 
supply more than they evolve in this excess, that is, aijove 
the haeis. Ko ftubstance containing a large amount of car- 
bon evolves more than a smalt portion of that carhon in tho 
temporary action occurring aliove the basts linej and tienco 
a large portion remainB unaccounted for by these ex|>en'- 
ments." 

The comparative ohaervations of Dr. Smith upon the four 
persons who -were the enhjecta of cxpeinment demijnst rated 
one very important fact; namely, that the action of different 
kinds of food upon respiration is raoditJed by idioeyncraaies. 
and the tastes of dift'erent individuals. For example, in ex- 
periments on his own person, certtiin articles which were 
agreeable to him excited the exhalation of earhtmic acid ; but 
in experimenting with the same articles upon Mr, Monl, to 
whom they were distasteful, he fomid the respiratory action 
diminished, 

Quit^ a number of observers have noted the influence of 
alcohol upon the products of respiration ; but the results of 
experiments have not been euth-ely unitbrm. Prout ob- 
served a constant diminution in the quantity of carbonic acid 
exhaled, under the influence of alcohol. This has been coniirm- 



E9FLUESCE OF WET. 



437 



edby tlieobservatioMBof Horn, Vierttnlt,an(l many others ; but 
HervicT' iind Stiint- Lager assort tliat tbe use of alcohol innireK&ea 
the exhdlatiim of carbonic a<:iJ.' In tbe experiments of Prout, 
a small quantity of wine tftki;n fiisting cuused tbe proportion 
Dt' carbuuic acid iu tbe espired air to faU iininediatety fixun 
4 to 3 |>arts per ]00. Diuiiig tbe four btmra fuUowiug, it 
oecillated between 3-40, S'lO, and 3. The adniinaKtratiou of 
a second dose, followed by some syiuptonis of intoxication, 
ditiiiinslied tbe pruportiuu to 2'TO per 100. Dv. Fyfe, of 
Edinburgh, showed that the depressinj; etfecta of an aleobolic 
exccsd were continued into the following day.' Dr. Fyfe also 
noted a fiict, ittiportaut in this connection ; nameiy, that tbo 
prolonged use of nitric acid and the condition of the eysteni 
mdnced by the adnunistratii>n of mercuriida were atteadiKl 
■with a eoiiBiderable diminution in the daily amount of car- 
bonic acid exhaled by tbe lunge. Iji addition, Prout dcmou- 
Btrated that the carbonic acid was diminished by the uee of a 
concentrated infusion of tea, and Horn noted the same effect 
attending sHwht narcotism pi'oduced by smoking tobacco.* 

The obscjTations of Dr, Smith, which were all made fast- 
ing, show a certain variation iu the elTecte of ditfereut alco- 
Lolic beverages. His reaulls are briefly thu following: 

*' Bmndy, whiskey, and gin, and particularly the latter, 
almofit always lessened the respiratory changes recordedj 
whilst mm aa conioionly increased them. Rum-aud-inilk 
had a very jtrononnced and persisteut action, and there was 
no effect on the sensorium. Ale and porter always increased 
them, whilst sherry wme leescued tho quantity of air in- 
"ipired, but sHgbtJy increased the carbonic acid evolved, 

' Milke-Edw»kds, Phifrinhiffir^ Pnriii, lft07, tome ii., p. 635, 
■ Ibid, IVouc took pogrtiEimte only of tlie proportion of rarbonic ncicl in 
the cxpiTc4 air, and not ol llic atcotulc quantity' exhulcl in a given iini«. 

' Frnw tLi^ observations of Prout, ¥y(&, nad Ham, i;itwl above, it is probable 
tliAl tbert are mm); mcdidtiAl aj^^nb; t><iipiiblc nf ilimiiiisliing ilic climiinallon, tiol 
only of cnrtjoSiit! aciil, Imt of ui'tii mid olhcr cSctemeulittoua moitCTH; but the 
direct oiperiiu^Dtd upon tliesL' pulnt» itre ffir, on accioutit of the diniciiUy iU e«ti* 
mating 1b« amount of exhelAtioii from tlie luiig§ for n sufiicicutly long period, 



43S 



XSIPmATICiN. 



" The volatile elemeuts of alcohol, gin, mm, Bherry, and 
port-wine, when iiilialed, learned tlie qtWDtity of carbonic 
aciJ exhaled, and usually lessened flie qaantity of air inhaled. 
The effect of tiue old port-wiiie was very decided and uni- 
t'f.iriij ; and it i& known tliat wiu^ aod spirits improre in 
aroma and be'iyiue weaker in alcohol l>y age. The escitO' 
respiratory action of ruiu is probuUly not due to ita volatile 
elements." ' 

From these facti*, it would seem that the rDijst constant 
effect uf alt-'ohol, and alcoholic liquors, &[ich as wines ami 
Bpirits, is to dtmini&h the exhalation of carbonic acid. Thi? 
effett i$ almost iiistahlaneous, when the ariii:les are taken 
into the stomach fastixig; and wtieti taken with the me&U, 
the iu(.-rease in carbonic aeid whi<;h hahituidly ac-oonipanies 
the pi-ocesa of digestion is materially lestwned. Kiim, which 
Dr. Smith found to be a rospiratury excituiit, is au psception 
to tliia rule. Malt liquors seeui to increase the exhalation uf 
uarbouitf acid. With regai-d to alcohol itself, Dr. Smith 
Bays 1 "The action of jiure alcohol was much more to increase 
thAji to le^^n the re^piriitury change-'^, and sometltuea the 
former eflect was well pronounced."* 

rteganiiug as one of the great sources of carbonic acid 
the development of this principle in the tisauos, whence it is 
taken up hy the blood, Dr. ^cuith attributes the grateful and 
Bootliing influence of tea, police, eati tiucne, ajid the otlier 
hcvL'i-ugL^ti width he clastieB as i-espiratory excitants, to their 
action in facilitating the removal of this principio from the 
system. Tlio proAtnce of curhonfc acid in the tiesnes and 
in the blood produces a senso of tnalahe^ or depresi*ion, 
which we should suppose would be relieved by any thing 
whieh faeilitates its elimination. It is undoubtedly this in- 
delinito &cuse of discomfort which induces the ac^t of siglitng, 
by which the air in the lungs \a more eftWtually renovated. 
Thij^ view is sustained by the fact that intollcctiial Uitijfuo 
and mental cmotiona diminish tiie exhalation of ciirlH>nti: acid. 



p. 731. 



*ZM.a(l 



INFLUENCE OF MCSCUULtt ACTISnT. 



439 



Apjolin cites an instance in w^liich the proportion of carl><>nic 
jicid in the expirations was reduced to 2*9 parts per 100 under 
the influence of mental depression.' 

"We Imve alreaJy nllnded to tlic modification in the ox- 
lialatiou of .-arbonic acid produced by tobacco.' 

LiJf'Uence of &€^p, — Alt wbo have directed attention to 
the iufiuenee of sleep Upon th« respiratory products liave 
noted a luarked diminution in the exhalation of carLotiio 
acid; but we agaiji recur to tUe e-tperiments of Dr, Siuilh 
for exact information on this point. Dr. Smith estimated 
the quantity of carbonic acid exhaled during six hours of 
sleep, at nighty at 4,128 cubic inches. Aceardiug to tbia 
ohscrver, thu quantity dnriiin; the nijjht is to the quantity 
during thn day, in complete repose, as 10 is to 18, During 
a light sle&p, the exiialation Tvas ]0'3!2, and during profound 
sleep, Si'O^ cuhic inches por nunutt>. 

We Liivc dluded to the great dirninutiou in the quantity 
of oxygen consumed in hibertiatiug animaU, while In a torpid 
cuudition. Keguault and Reiset foutid that a marmut in 
luhenintiuu couBumed only -^^ of the oxygen which ho used 
in liig active condition. In the aaine animal tliey noted an 
exhalation of earboiiic acid equal lo hut i[lt3e more than half 
the weight of oxygen ahsorhed; sio that in this condition the 
diminution in the exhalation of carbonic acid \a proportion- 
ately even greater than iu the consumption of oxygen.' 

Injivence of MancxUar Aotivitt^.—AM observers, except 
Prout,' agree that tliere is a considerable increase in the 



»S«;Inigc437. 

* REi]Niit;Lt^ n lisiSET, Ainraltt de Chimit ef tft Phiftique^ Sine g^rie, totni? 
tsvi^ p, 4411. The macinitt wmBumpti in five d»jB 13,089 gnuntnc* of oxygun, 
tmi esliHlc4 7,l"4 gniminca of cnrbonic acid. 

' ?nji]t ouly nolM Itic propoitiuD, of c&rbonic acid in tbe «spircd ulr; ani] o^ 
eicrdse iiatJ the effucl of luimediateiji uud Urgelj iacruiB'ijgg Hie numtier at rc^pl- 



440 



BEfiPIBATIOrf. 



exhalation of carbonic acid dariag and immediately follow- 
ing muscalur exercise. In insects, Mr. Newport lias tbunil 
that a, greatLT f|uaiititj is Bouietinies cxLialed in an huur of 
viulent agitation, than in twciity-tijur Iionw of repose. In a 
drone, the extialation m twenty-four hours was 0-30 of a cubio 
inch, and dm-liig violent muscular exertion the eshnlationj 
in one lioui" was 0"34.' Lavnisier recagnizeJ the gi*eat in- 
fluence of iHtiscular activity xipou the respiratory changefi. 
In treating of the coneitmptiou of oxygen, wo have quoted. , 
hia obserrationg on the relative quautitiea of air vitiated in. 
repose and activity, 

Vierordt, in a number of observations on the human 
Buhjoct, ascertained that moderate exei'cise incnased the 
averau'eqnantttyof air respired per minute bynearlynineteen 
cubic inches, and that there Tva* an increase of 1*107 cubic 
inches per minute in the absolute quantity of carbonic acid 
exhaled.* 

The following i-esulta of the experiments of Dr. Edward 
Smith on this subject are very definite and satisfactory: 

In walking at the rate of two miles an liuur, the exhala- 
tion of (.larliouic acid during one liour \vn& equal to the quan- 
tity produced during 1^ hour of repose, with (bod, and 3^ 
hours of repose, without food. 

Walking fit the rate of three miles per hour^ one boar, 
was equal to 2| bout* -w-ith, and SJ hours without food. 

One hour's labor at tlie tread-wheel, while actually work-' 
ing the wlieel, was equal to 4^ hours of rest with food, and 6 
hours without food.' 

The various observers we have uited have remarked that 



ntor; moTemrata mad Ihe (|uantity at tir pualug thmu^h the litb^ uid i* *t 
huvu aieen ihe cjaanUt^ of cnrbonic aciil in ttie eijiircd nir b (ucreiseil ta propa(> 
|3»n tu die leii'^h of time thiit the air Tviniuiiia iu ibe lungi, w« out euil; sm lb« 
Kiirvc of error in SiU obsomidoa*, 

' MiL\K-E»wj.KiKK Ph)/tv>l>f{nf, Uime iL, p, SSO. 

* C'lidapadia of Anatomy uiu^ S'kjfnoioffjf, vol ir., put L, p. $4& 

■ Op. eit., ft. 7U. 



IKFLTJENCE OF MOISTURE A^•D TEMl'ERATTBE. 441 

when muscular exertion is carried eo fiir as to produce great 
fatigue and exhauBtioii, the exhalation of carbonic acid ia 
notablr diminished. 

Infiuence of Moisture and Temperatiwe. — Lehmann huB 
ehown that the exhalation of carbonic acid is much greater 
in a moist than in a dry atmosphere.' This conclusion was 
the result of a number of experiments on birds and animals 
confined in air at different temperatures and different degrees 
of moisture. He found that 35| oz. av. weight of rabbits, at 
a temperature of about 100° Fahr., exhaled during an hour 
before noon, in a dry air, alwut 15 cubic inches of carbonic 
acid ; while in a moist air, at the same temperature, the ex- 
halation was about 23 cnbic inches. 

Disr^arding observations on the influence of temi>erature 
in cold-blooded animals, as inapplicable to the human sub- 
ject, it has been ascertained that the exhalation of carbonic 
acid is much greater at low than at high temperatures, within 
the limits of heat and cold that are easily bonie by the human 
subject; thus following the rule which governs the consunij)- 
tion of oxygen. Crawford, in his experiments on animal heat, 
was the firet to call attention to this fact,* Since then it 
has been confirmed by numerous observations on animals. 

Tlie experiments of Vierordt on the human subject show 
that there is au increase in the exhahitiou of carbonic acid of 
about one-sixth, under the influence of a mo^lerate diminution 
in temperature. In these observations, the low temperatures 
rauged between 37'5° and 5i>°, and the high temperatures be- 
tween GO'S" and TS'o" Fahr. Ue found the quantity of air 
taken into the lungs slightly increased at low tem])eratnre3. 
The absolute quantity of carbonic acid exhaled per minute 
was 18*27 cubic inches for the low temperatures, and l.>*7y 
cubic inches for tlie high temperatures,* 

■LKiniAm, PhwoliM/iml Clififiifni, riiiUulcli>Iii.i, 1835, vol, ii., !•, 444. 

* Milkx-Edwards, cp. cU,, p. 548. 

* Ibii, p. MI. 



442 EE8PIBATION. 

Infiuence of the Season of the Year. — It has been pretty 
well established by the researches of Dr. Smith, that spring 
u the season of the greatest, and fall the season of the least 
activity of the respiratory fiinction. 

The months of maximum are : Jannary, February, March, 
and April. 

The months of niinimura are: July, August, and a part 
of September. 

The months of decrease are : June and July. 

The months of increase are: October, November, and 
December." 

"W. F. Edwards, in 1819, showed in a marked manner 
this influence of tlie seasons upon the respiratory phenomena 
in birds. In a series of very curious observations, which he 
repeatedly veriiied, it was demonstrated that the increase in 
the activity of respiration during the winter was to a certain 
extent independent of the immediate influence of the sur- 
rounding temperature. In the month of January he confined 
six yellow-hammers in a receiver containing 71"4 cubic inches 
of air, carrying the temperature to from 69° to 70** Fahr. 
The mean duration of their life was 62 minutes 25 seconds. 
In the months of August and September he repeated the ex- 
periment on thirteen birds of the same species, at the same 
temperature. The mean duration uf life was 82 minutes.' 

These experiments have an important bearing on cor 
views concerning the essential nature of the respiratory func- 
tion. They seem to indicate that the respiratory processes 
are intimately connected with nutrition. Like the other nu- 
tritive phenomena, they undoubtedly vary at different sea- 
sons of the year, and are to a certain extent independent of 
sudden and transitory conditions. During the winter, more 
air is habitually used than in summer, and the respiratory 

' Higuina de Recherche* Eeperimentaiea lur la Reapiralion.— Journal de /a 
Pht/tioioffU, 18A0, tome iii., p. t>19. 

* VV, F. Edwari«, De tlnfiuence de* Agent Phytiqua nu- la Vie, Puis, 1824, 
p. 800. 



BELATIONd BETWEEN OXYGEN AND CABBONIC ACID. 44:3 

processes cannot be immediately brought down to tbe eura- 
mer standard by a mere elevation of temperature. 

ObservationB on the influence of barometric prraanre are 
not sufficiently definite in their results to warrant any exact 
conclusions. 

Some physiologists have atteuipted to fix certain hours of 
tlie day when tbe exhalation of carbonic acid is at its maxi- 
mum, or at its minimum ; but the respiratory activity h in- 
fluenced by such a vaiiety of conditions, that it is impossible 
to do this with any degree of accuracy. 

Melatimia beiioeen the Quantity of Oxygen consumed and tlie 
Quantity of Carbonic Acid exhaled. 

Oxygen unites with carbon in certain proportions, to form 
carbonic acid gas, the volume of which id precisely etiual to 
the volume of the oxj'geu which enters into its compu^itiou. 
In studying the relatione of tlie volumes of tliese gasra in 
respiration, we have a guide in tlie comparison of the volumes 
of tbe inspired and expired air. It is now generally recog- 
nized tltat tbe volume of air expired is less, at an equal tem- 
perature, than the volume of air inspii-ed. Assuming, then, 
that the changes in the expired air, oa regards nitrogen, and 
all gases except oxygen or carbonic acid, ui*e intsigiiiticunt, it 
must be admitted that a certain quantity of the oxygen con- 
Biimed by tbe economy is unaccuuiited tor by tbe oxygen 
which enters into the composition of the carbonic acid ex- 
haled. We have already uoteil that from -V ^*J o'ji "'" "l^out 
1'4 to 2 per cent, of tbe inspired air is lost in the lungs ; ' ur 
it may be stated. In general terms, that the oxygen absorbed 
is equal to about five per cent, of tbe volume of air inspired, 
and the carbonic acid cxlialed only about four iwr cent. A 
certain amount of tbe deticiency in volume of tlie expired aii 
la then to be accounted for by a deficiency in tlie exliahitiou 
of carbouic acid. 

■ See iinge 405. 



444 



BESFIBA-nON. 



Tlie experiments of Reguault imd Reit^t, to wliidi I're- 
qneiit retVri'nee luie been iiiatle, liave ii most importftnt bear- 
ing on the question under consideration. A& these observers 
wore able lo cjirefull y measm^ the entire fiuaiitiTtes of oxygen 
eonfliM!ie<I and cai'buuiu acid produec-J in a given time, tbe 
relation between the two gases was kept conslanllj- in tictt. 
Tbcy found great vjiriHtlons In this relatlun, mainly depwidenl 
upon tbe rej^imeti tif the animal. The total loss of oxygen 
was Ibund to be inniili gi-enter in carnivorous than in hcrbiv- 
orons nniuiala; and in animals tbat could be Bubjecled to a 
mixed diet, by regulating the Ibod, tliia was made to vary be- 
tween the two exti'emea. Tbe mean of seven experimente on 
dogs sbowed that for every 1,000 parts of osyo^en consumed, 
745 parts were exhEiled lu the form of cflrbonic acid. In six 
experinjents on rabbits, tbo mean wats 919 for everj" 1,000 
parts of oxygen.^ 

In animals fed on grain?, the proportion of carbonic acid 
exhaled was greatest, sumctiraes passing a little lieyond the 
Volume of oxygen consumed. 

" The relation is nearly constant for animals of the same 
Bpeciea which arc subjected to a jierfectlj' uniform alimenta 
tion, as is easy to realize as regards dogs ; but it varies not- 
ably in animals of tbe same speoies, aud in the f^ame animal, 
Biibmitted to the same regiraen, bat in which we cajmot reg- 
ulate tbe alimentation, aa in fowls."' 

When herbivoroufe animals were entirely deprived of food, 
the rehition between thegabet^ was thebume a& in curuivoruua 
animals. 

Tlio finul result of tlie experiments of Kegnault and 
Rciset was, that the "relation between the oxygen contained 
in the carbonic acid and the total oxygen consumed, variee, 
in the same animal, from 0'fi2 to 1'04, according to the regi- 
men to which it is subjected." 

' REQKArLT Had Rkiekt, JlccAeixAu Cfiimiijuct mr la UtapiratUiu ^Arttitt/a 
U Chiinit d de Pk^/ti^ur, 3me siric, totnc xi»i. 

Mljii!., p. 6U, 



S0DBCE8 OF CARBONIC ACID EXHALED. 445 

These observations on animals have been confirmed in 
the human subject by M. Doyere, who found a great varia^ 
tion in the relations of the two gases in respiration ; the vol- 
ume of carbonic acid exhaled varying between ]'087 and 
0*862 for 1 part of oxygen consumed.' 

The destination of the oxygen which is not represented 
in the carbonic acid exhaled is obscure. Some have thought 
that it unites with hydrogen to form water ; but there 
is not sufficient evidence of the formation of water in the 
economy, for researches have failed to show that there is 
more thrown oflf from the body than is taken in with food 
and drink. 

The variations in the relative volumes of oxygen con- 
sumed and carbonic acid produced in respiration are not 
fevorable to the hypothesis that the carbonic acid is the re- 
sult of a direct action of oxygen upon carbonaceous matters. 
We should hardly expect a definite relation to exist between 
these two gases in respiration, when we find carbonic acid 
exhaled in the absence of oxygen, as has been shown by the 
experiments of W. F. Edwards and Geo. Liebig. 

Sources of Carbonic Acid in the Expired Air. — All the 
3arbonic acid in the expired air comes from the venous blood, 
where it exists in two forms ; in a free state in simple solution, 
or at least in a state of very feeble combination, and in union 
with bases, ibrming the carbonates and bicarbonates. That 
which exists in solutiou in the blood is simply displaced by 
the oxygen of the air and exhaled. The alkaline carbonates 
and bicarbonates of the blood, coming to the lungs, meet 
with pneumic acid (discovered by Yerdeil in 1851), and are 
decomposed, giving rise to a farther evolution of gas. It is 
pneumic acid which gives the constant acid' reaction to the 
tissue of the lungs. This principle is found in the pulmo- 
nary parenchyma at all penods of life, from which it may 
be extracted by the proper manipulations, and obtained 

* Milne-Edwards, JPh^nologit, tome iL, p. BM. 
29 



440 



EESriBATION. 



in a crjetalHne form. Its qusmtitj is not very great. TLe 
lungs t'l' a feiusile wlio sitftered death Lj decapitation eon- 
tained about 0'77 of a p;rain.' 

The action of piieuraic acid upon the l>icarUoiiat*'B in the 
blood is exeinphtied in a marked manner by certftin experi- 
ments of Bernard. When bicarbonate of soda is injected 
into thjj ju^ilar of a. living animal, a rabbit, for example, it 
is decomposed as fa^t as it gets to tbe lungs, and carbonic 
auid is evolved, TliJa experiment producM no inconvenience 
to tbo animal when the bicarbonate is introdnced slowly ; but 
"ivlien it is injei;ted in too gi-eat quantity, the evolution 
of gas in tba luuga is so great as to fill the pulmonary etruo- 
ture and even tlio heart and great vesaels^ and death is the 
result.* 

ExJudatio-n. qf Watery Viipor. — The fact that the expired 
air contains a considerable quantity of watery vapor has long 
been recognized; and most of tlie earlier experiraentera who 
directed their attention to the phenomena of respiration 
made the estimation of the quantity exhaled, and the laws 
which regulate pulmonary tninspiration^ the subject of in- 
vestigation. It ie evident that there must be many cir- 
cumstances materially inlluencing this process, Bueh as the 
hygronietric condition of the atm^jsphere, temperatm-e, ej[- 
tent of respiratory surface, etc., "which are of suflieicnt impor- 
tance to demand si^ecial consideration. In many points of 
view, also, it is interesting to know the absolate quantity of 
exhalation from the lungs. 

' Roni^^tid Verdeil, Chimi Anatomigue tt PA^'oIo^Uf^ Farui, 19B3, Utma 
ii, p. Am. 

' O/'.eit.^ temp L, p. 100 Tlie&ejeipcrlmonta rcfyrred (o the iJeeompcwIUon fyt 
cyanid'; C'f poUeslum in tlie lung?, OS n"ell aa IjicarboOfttt! of BOiij. Tbej wq*? 
publidlicii ill the ArtJihet Giiuralrt in 1549, bcfora tli« dkscqTcrT of |^ni.'uraJt 
M.<id, a.ijj I](>raiirJ i;iprc«seJ Rurprise ttiat the lito siibfitanccs cipeHmented upcnv 
irbich rci|uired bii ucld for their dccoraiKisiLiaa, ebouti] be ducompoteJ in unl- 
koUtie fluid like tbo lilnod. Tliougfi [aaii>u ft'itliout & knowledge of the ubuaes 
of pncuniic acid, tttc C'b^'rvBiiotta none tbe leas Uliutraled in phj-sioloeinJ 



EXHALATION OF WATEBT VAPOE. 



44T 



"Wlien iLe surrounding atrnoa^iliereliaa a temperature below 
iO° ur 43° Falir., a distinct cloud is produced by tbe coudensa^ 
tion of the vapor of tbe bi'catb.. By breathing upon any 
polished surface, it is momentarily taroislied by tbe condenseU 
iiiuisture. Tliougli the fat^t that watery vapor is contained in 
tlic breath ia thus easily demoustrated, the estimation of its 
abeolute quantity presents difficulties ■which were not overcome 
by tbe older physiologists. Hales collected the vapor of the 
breath by expiring thronglt wood ashes,' which was the first 
attempt to eatimate tlie amount of tlua exhalation by alisorp- 
tion. With the present improved methods of analy&is there 
are many very accurate means of eetituatiug watery vapor. 
One method ia by the «se of Liebig'a bulba tilled with sul- 
phuric aciti, or tubes tilted with chloride of calcium, both of 
which articles have a great avidity for water. Froiu a large 
number of observations on hia own persoa and eight others^ 
collecting the water by sulphuric acid, Valentin makes the 
following estimate of the weight of water exhaled from the 
lungs in twenty-four hoars: 

In his own person, tbe exhalation in 24 hours was 6,055 
grains. 

In a young man of srnall. size, the quantity was 5,049 
grains. 

In ft student rather above the ordinary height^ the quan- 
tity wa3 11,930 grains. 

The mean of his observations gave a daily exhalation of 
8,333 grains, or about IJ lb. av.* 

' Eaisb, Statical Eia<3Jjii LoDdon, 11S9, roL ii., p. S'iO. Sain^torias, ia 
1*14, waa lUe firat ( WiLSE-EtiwiRiis, I'hiftirAogie, vol. il, [i. 8l>3) to fltleoipt thd 
esliniutioD of tie ciilialatton of vnpor of waler froin tha body by comparing llie 
gUD ia iTC^glit ilue to till? lageition of albuDDts wit]] tlii! ]u85 by IraiuipiratioD, 
We p«»a ovCT the tstimAtea qf Iinroisicr oiid Sigiiin, Keill, AbGnicibj-, and 
otbcn, and give only the more eiact rctiults obt&lQcd by Va]«n<if>. Daltvo, 
eatiiDdtiing the (luoBtitj of n.ir pa^isiag Lbro%'1i tic lim^ ia rGfi pirn. lion, aud as- 
Biuoing tliat it ptuiBca out of Ihc luQijA saluTAltid trith watcrj' vapor, makc-t) an Kr 
tlmate of tbs iatnl esbalation im the twcfitf-fduc houTB, which correipunda pr«ttj 
closely with the tesulU obUiuicd by TaJtntin. 

*UjU(i<Edwa8ds, rtp. cU., p. 621. 




44S 



EEBPmATIOS, 



The extent of reepiratorj enrface has n very market! in* 
fluence oil the qnsntitj' o£" ivalery vapor L-xlmliid, Tbis t'aat 
is very well shown by a conipnrison of ihe exlmtntioo in tho 
oilult and ia old age, wlien tlie extent of resjiinit.r>ry surface 
13 much diniTJiished. Bairal found tbe eshalution in an old 
nijin less t!i*ii balf tbat of the adult." 

It Es evident tliat the absolute quantity of vapor exbalcd 
is inere.i&ctl wben respiration ia accelLTflted, 

Tbo quantity of water in tbe blood also exerts an impor- 
tant influence. "Valentin found that tbe pnlinonarj transpira- 
tion was more than dowbled ip a nifiu immediately afterdnuk- 
ing a large quantity of water.' 

The vjijior in the expired air is derived from the entire 
surface which is traversed in respiration, and not exdnsively 
fi-OQi the air-cells. The air wlittrh paesea into tlie lungs de- 
rives a certain amount of moisture from the moutli, naree, 
and trachea. The great viiseularity of tlie inncoiis metiihranes 
in these situations, as well as of tbe air-cells, and tbe great 
number of mucous glands which they contain, eeire to keep 
tbe respiratory surfaces eoiitinufllly moist. This is iniportaut, 
for only motst membranes allow the free passage of giieeSf 
which is of course essential to the process of respiration. 



JSxfioIaiton of Ammonia. — The most recent and extended 
obBerrationB on tbe exhalation of ammonia by the lungs, are 
those of Dr. Kichanlson, to whicb we bave already alluded 
in treating of the coagulation of tbe blood. In more tlmn a 
thousand experiments, made upon persona of both sexes, and 
on varions of the inferior animals, with but one exception, a 
notable quantity of sinmonia was fouud in the expired air. 
Dr. Richardson found the quantity very variable at different 
times of tlie day. At certaia periods it is absent. 

' UiLKE-EnwABDS, ep. tit., p. 625, note. 

* Iliid,, p. Ciii, note. Ii h&a not bMH tliouglit neccsuirj' to disciuw the To 
fliicnwes ol ilry aad xLii>Ut atiuosphen>, bnroui^tric prvs^iire^ and laDpemiiira', 
whioh BTD piicol^ phf«ieA] la their ebaraei^. 



EXHALATION OF ORGASIC MATTEH. M9 

In a number of observations made on liis own person, tlie 
following variations were noted :' 

Ou rising in the morning, atter a sonnd night's rest, the 
breath contained no ammonia. 

In the evening, when fatigued and exhausted, and after 
exercise, tlie exlialatiou was generally considerable. 

During a high temperature the exlialation is considerable, 
especially after exercise ; but dimug cold weather the exlia- 
lation is very slight, or it may he absent altogether. 

The amount of ammonia exhaled is greatest at tlie end 
of an expiration. If short and rapid expirations be made, 
the exhalation ceases until the respirations become deeper 
and more prolonged. 

Ammonia has long been recognized as an exlialation from 
the liuman body in liealth, from the skin as well as the lungs. 
Dr. Richai'dsoii calls attention in his essay to the observa 
tions of Mr. Reade, Dr. Keuling, Viale and Latini, and 
others on this subject. Eeuliug lias sliown that the quantity 
of ammonia in the exjnred air is increased in certain diseases, 
particularly in uneniia.' Its characters in tlie expired air 
are frequently so marked, tlutt patients who are entirely 
unacquainted with the jiatbology of ura'inia sometimes 
recognize an ammouiacal odor in their own breath. 

Exhalation of Organic Matter, etc. — The pulmonary snr- 
face exhales a small quantity of organic matter. Tliis has 
never been collected in sufficient quantity to enable us to 
recognize in it any peculiar or distinctive proi)erties, but its 
presence may bo demonstrated by the fact that a sponge 
completely saturated with the exhalations from the lungs, or 
the vapor from the lungs condensed in a glass vessel, will 
nndei^o putrefaction, a property distinctive of organic sub- 
stances. 

It is well known that certain sul^stances which are only 

' The Cmmeoflht Coagulation of the Blood, London, 1857, p. 360 elteq. 
* In Lkbiunn's Phifnologieal ChemUtry, Philadelphia, 1806, toL ii., p. 434. 



^0 



EE3I'iaATI0N. 



Occasionally fmin'l m the blooul may be e^liminated by ttio 
lungs. A]i;oLul is |Jiii-tly remuved fruin the syelem in tliia 
way; and ibi presence, with certain odoryus principles, in 
tlie brejith is pretty constaot in those who take liquors ha- 
bitnaliy m considerable quantity. The odor of giirlic*, onions, 
tiirpentjue, and many other principles which are taten into 
the stomach, may be ret'ognized in the expired air. The 
Inngs are among the important organs ibr the elirainatton of 
foi-eign matters fi'om the system. 

The action of thy hiugs in the eliniination of certain gaacs, 
which are poiecinoua In very amall quantities when they are 
abeorbeil in the lunge ai;d cjirried to the general Byeteiu in 
the arterial Wood, is very well shown by the experiiuenta of 
Bernards Sulphuretted hydrogen, which producer) death in 
a Iiird when itexidta in the atmospliere in the proportion of 
1 to 800, may be taken into the atoinach in solution with 
inipmiity, and even be injected into the veuou3 system ; in 
both jnstancca being eliminated by the lungs with great 
proraptnees and raiiidity.' Nysten showed that the carbonic 
oxide, one of the moat violent and rapid in its effects of any 
of the poiflonoua gases when inhalcj.1, could he injecte<l into 
the veitis with irnpunity, by simply taking care to introduce 
it only as rapidly as it is alfsorbed bj the Woo<l.' 

llio lunga, then, while titey present an immense and rap- 
idly absorbing surface for volatile poieonous substances, are 
capable of relieving the system of Bome of these suli&tance& 
by exhalation, when they Und their way into the veins. 



Puris, lS."i7, p- 58, In uu ■•xtH'i'iLiiuut wi a tlog iff niwUtim siro, injectUiK o liiUe 
mure Uihd » fluid dr&vlLm gf h-uIlt BAlurak^d wiili sul|iliiin-Ui^(l bydn.)<>vij inkj ibe 
jUguIiLf V(.'i[|, the gny ^mk ClXv^y^A ^3iugsl inatiinll]' iu the i-ipired ur, und th« 
Asimiil aulTL-rcU uu luuuiivt.'tJt.-ii(.'(; froui tb« upcni(ji*n. T!i« gw ippewi-ti Id Uiq 
breaCli in sUt;-Src 'jeraaJft, wlim nbotii na ttnivii: uf tlio solutiun wis ii^i.-cU.iJ 
tfLto the rectnni. We hsTe repentrily veri9«i the wptrlment of Bcrnwd ihoiflag 
the blmost LiurranlHiK^fliis elifniuatiMi of ihie gas hy Mm Luog^ vhcn injected intu 
the TeibA. 

* NiKiC*, RecherAM ik F/iifrioLiffit, cte, T&tii, ISll, p. 81 d te^. 



EXHALATION OF NITBOOEN. 451 

Bxhcdatlon of Nitrogen, — The latest and most accurate 
direct experiments, particularly tliose of Regnault and Reiset, 
show that the exhalation of a small quantity of nitrogen is a 
pretty constant respiratory phenomenon. From a large num- 
ber of experiments on dogs, rabhits, fowls, and birds, these ob- 
servers came to the conclusion that when animals are subject- 
ed to their habitual regimen, they exliale a quantity of nitrogen 
equal in weight to from -^ to -^ of the weight of oxygen 
consumed. In birds, during inanition, they sometimes observ- 
ed an absorption of nitrogen, but this was rarely seen in mam- 
mals.' BouEsingault, by the indirect method, estimating the 
nitrogen taken into the body and comparing it with the en- 
tire quantity discharged, arrived at the same results in ei- 
perinienta upon a cow.' Barral, by tlie same method, con- 
firmed these observations by experiments on the human 
subject.' 

In spite of the conflicting testimony of the older physi- 
ologists, there can now be no doubt that, under ordinary 
physiological conditions, there is an exhalation by the lungs 
of a small quantity of nitrogen. 

' Rkonault and Reiset, op. ciL, Annala <h Chimie H de Fkynqae, Sme 
Urie, tome iitI, pp. 610, 511. 

' BocssiNOACLT, Mimoiret dt Chimie Agrifole el de Fkysiologie^ Fuia, 1664, 
pp. 1-24. 

* LONOBT, PhyeioloffU, Paris, 1868, tome L, p. 6BS. 



CHAPTER XIII. 

CHANGES OF THE BLOOD IN BEaPIHATION. (JTamatOStS,) 

DiRerence in color between arterial and venous blood — Comparison of the giuee 
in venous anil arterial blood — ObservnUona of Magnus — Annlj^b of the blood 
for gases — Relative quantities of oxygen and carbonic aeid in venous and kt- 
terial blood — Nitrogen of the blood — Condition of the gases in the blood — 
Uechanism of the interchange of gases between the blood and the air in tho 
lungs — General diETerencea in the composition of arterial and venous blood. 

It is to be expected that the blood, receiving on the one 
hand all the products of digestion, and on the other the 
various products of disassiniilatiou or decay of the tissues, 
connected witli the lyinpliatic system, and exposed to the 
action of the air in the hings, should present important dif- 
ferences in composition in different parts of the vascular 
system. 

In the first place, there is a marked difference in color, 
composition, and properties, between the blood in the arte- 
ries and in the veins ; the change from venous to arterial 
blood being effected almost instantaneously in its passage 
through the lungs. The blood which goes to the lungs is 
a mixture of the fluid collected from all parts of' the body ; 
and we have seen that it presents great differences in its 
composition in different parts of the venous system. In some 
veins it is almost black, and in some nearly as red as in the 
arteries. In the hepatic vein it contains sugar, and its organic 
constituents and corpusclea are diminished ; in the portal 



CHANGES OF THE BLOOD IS EE8PIEAT10N. i53 

vein, during digestion, it contains materials absorbed from 
the alimentary canal ; and finally, there ia every reason to 
suppoae that parts ■which require different materials for their 
nutrition, and produce different excrementitious principles, 
exert different influences on the constitution of tlie blood 
which passes through them. After tliis mixture of different 
kinds of blood lias been collected in the right side of the 
heart and passed tlirough the lungs, it is returned to the left 
side, and sent to the system, thoroughly changed and reno- 
vated, and, as arterial blood, has a uniform composition, as 
fer as can be ascertained, in all parts of the system. This 
fact has been proven by the direct experiments of Beclard, 
who analyzed blood from the abdominal aorta, the carotid, 
temporal, occipital, crural, and epigastric arteries, in the 
same animal during life, and found the composition identical 
in all the speciniens. His experiments were performed on 
horses and dogs, and care was taken to draw but a small 
quantity from each vessel, so as not to change tlie constitu- 
tion of the fluid.' The change, therefore, which the blood 
undergoes in its passage through the lungs, is the transfor- 
mation of the mixture of venous blood from all parts of the 
organiem into a fluid of nnitbrm character, which is capable 
of nourishing and sustaining the function of every tissue and 
organ of tlie body. 

Tlie capital phenomena of respiration, as regards the air 
in the lungs, are loss of oxygen and gaiu of carbonic acid ; 
the other phenomena being accessory and comparatively un- 
important. As the blood is capable of holding gases in solu- 
tion, in studying the essential changes which tliis fluid un- 
dei^es in reapii-ation, we look for them in connection with 
the proportions of oxygen and carbonic acid before and after 
it has passed through the lungs. In respiration, the most 
marked effect on the venous blood is change in color. 

' Archive! Giniralet de Andtcine, 4me afirie, tomo xviiL, p. 123 ; and B^rjlrd, 
ngnotogit, tome iil, p. 869. 



4£^ 



liESPTEATIOS. 



Dtference in Colar tHwceti Arterial and Vtrtioui BJ<»)^. 
— We bnve alfeadv considered ttU in treating of the propei-- 
tiefi of the blood, and shall onlytake up iit this connecUoa the 
cause of the reriiarka.b]e clinnge in tho color of t!ie blood 
in the lungB^ Thia cluiuge is inataatancous, and, loiig be- 
fore the discovery nf oxygen by Priistley^ was recognized 
hy Lower^ Goodwyn^ and others, as due to the action of 
the air. (See page 100). 

The celebrated experiment of Bichat. showed tlie effect 
on the Rolur of the blood in the arteries^ of preventing the 
access of tVesh air to the lungg. This observer adapted a 
Blop-cock to the tfacbea of a dog, bj which he eonld regu- 
late the entrance of air iuto tho luugs^ and expo&ing the caro- 
tid artery, adapted a eiiiall one to this veeseh TTheu hn pre- 
veated tlio air from getting to tho InngB by closing the 
Btop-eock in the trachea, the blood heeame black in the 
artery, but regained its florid hue when air was readmitted 
to the lungs.' 

The ittfluence of air in changing the color of venous blood 
may be aoted in Ijlood which haa been drawn from the Ixwiy ; 
Q& is exemplified I>y the red color of that portion of a clot, 
or the surface of detibrinated venous bloodj which is exposed 
to the liir. If we cut into a clot of venuna bloody the interior 
is almost black, but beecmea red on expoeure to tlie air for a 
very few seconds. 

We have been in the habit of illustrating the physiologi- 
cal iiitluence of the air on venous blood by the following 
simple experiment: Removing the luisgs of an animal (a 
dag) just killed, the nozzle of a syringe is secured in the pul- 
monary artery by a ligature, and a cannla, connected with a 
robber tube which empties into a glass vessel, la secured in 
the pulmonary vein. Adapting a bellows to the trachea, we 
imitate the pro<',csa of reapiration ; and if dofibrinated veuoua 
blood be carefully injected through the lungs, it will be retum- 

par F. Hj.onitii8, Paris, 1829, p, 3SU. 



CHANGE TN COLOR OP TDE BLOOD 



455 



^dbythe pulmonary vein with tlie bright-red colarof arterial 
blood. "Wlien the itrtifit^iiil rtspiratiaii is interrupted, the 
blood paefiGS through tlie lungs without cliange.' In expos- 
ing the thfiraeio organs, and keeping «p artiiirial respiration, 
repeating the celebrated experiment of Robert Hook, made 
before the Rojal Soelety in lOti-t, we can see through the 
tliira walls of the auricles the red color of the blood on the 
left side contrasting with the dark vetious blood on the right. 

Since the discovery of oxygen, it has been at^certaiiied 
that this i& tlie only constituent of the air which is capable 
of aiterializiag the hloeil. Priefltley eliowed that venoua 
blood is not changed in color by nitrogen, hydrogen, or car- 
bonic aeid ; while all these gnsea, by ditiplaL-iiig oxygen, will 
change the arterial blood frorci red to black.' 

The element^ of the blood which absorb the greater part 
of tlte osjgen are the red corpnscles. While tlie plasma will 
absorb, perhaps, twice as mueh gas as pure water, it has been 
ahow,Ti by Magnus and Gay-Lussac that the corpuscles will 
absorb trom ten to thirteen times as much.* By some the 
proportion t5 put niueh higher. Tlic red corpuscles may be 
considered as the respiratory elements of the blood. It is 

' Thifl deinonstnititm is very Btrikiog;, espccUllj if we uae & eyrin^ nltli & 
douljlo DDKzlet one paint si^ciirm] in ifae fiulnionnrjr arttn', aod ibc uthei' simply 
o«rrni»g the Mood by a rubber tube intii a ginsfl seSsel. RcireifDug llie Wood 
irbivb pnmea througli the Liiiiji^'Sr nod tliat wliiih einnplj passoa through tbo Liibo, 
into two tall glniv vt^g^c-la, tlie oae U of u bright rod, anil the olher ret^tis It* 
d»ir|[ i.tiloF. In preparing for the experiment 3i is necessarv, icnnieilialelj niter 
remoVED^ iim liing^ IVoni tlic atiitna], to iiijoct Ihetn iritb a, Ulllv dcfibriuatiU blood, 
K u to wmova the coaguktinj; blood from ibe pulmunarj- capiHnrlva, wbigli would 
utliervriae bccoioo obsimuicd. The inji^-eiio't ebould hs mudt,' g^ily (uiJ grii JuaUy, 
to avoid ezIrivuAtian, Di^Ql^rinutcd oi-blooJ may ho u?c>l, Ths nio^l canTcn- 
lent iray to aeciirc the cnuulto in the veiselB is to putih th<.>m into the giulinonurr 
ntety through the rigiat T'entrii^le^ and kito tlic pulnioQU'; vem through Uic Ivft 
anridA. 

' An AettMHl of an Erperimmti madt hy Mr, Eook^ of Pratrving AnitiuiU 
ilive ifi IS'iv<it\p thrnwjh their Lunffa lei'tft BtUfita. — PMiatophital 7VwiiKinfiOH<, 
Lfinrfon. IfiliT. v^il. U., p. 689. 

* RooiK ET VKrineiL, op. tit., tottm I, p. SS. 



i5Q 



SESPTBATION. 



andonbteiUj' true that the corpUBcle*, deprived of tlieir natu- 
ral plasma, are not changed in color by being exposed to the 
air, or even to pnrc o!cygen. Dr. Stevens, after rcmoiriTig 
the serum frrun a clot by repeated waslungs with pure writer, 
found that the color remained l)lack wheu expijaed to the air/ 
but was reddened by the addition of its seniin, or certaia 
Baline sohitions. From this be reaeoned that the red color of 
ai'terial bitjod ia due to the saline constituents of the plnsiua, 
ThiB is true; but the saline conRtEtuents of the plasma atTect 
the uotor indirectly, by nniintainin^ the aiiatoinlcal iniegrity 
of the corjinBcles. If blood be received fi'om a vein into pure 
water, it remains almost blaet, hovrever long it may l>c ex- 
posed to the air," fi-oni the faet that the corpuscles arc de- 
stroyed. Tbvse facts ary only additional evideuce of the 
function of the red corpusclea in absorbing oxygea and car^ 
rying it to the tissues. According to the late researches 
of I'Wuet, which have been couiinned by L. Meyer, the toI- 
ume of oxygen fixed by the corjniBcles is about twenty-five 
times that which is dissolved in tbo plasma.' 



Comparison oftfie Gasm in Venous and ArUrud Blood. — 
The demonstration of the fact that free oxyg;ea and carbonic 
acid exist in the blood, with a knowledge of the relative pro- 
portion of these gases in the blood before and after its pa^ 
tage through the lungs, Je a |>oiiit liHrdly second in iniportauce 
to the relative composition of the air before and after respi- 
ration. The idea euuneiated by Mayow nlwut two hundred 
yeara ago, that " there is eoinetbing in the air, abaolutelj 

' William Stbtehs, Ohnrrvatiim* in tfit H''nhh<i "ixiliiffaMd FroprrSm */ ^ 
Btfiftd^ London, 1832, p, 362; ntitl Philotopfiifol Trantii<Uii>Ht, 18SB. 

' Mtlsi-Edwards, PA^-aloffie^ tome f., p. 4?8. 

' LoxQEi, Tmiti lie Pfi-jaiUuffie, rurip, 1B68, lumo i., p. 70S, Fcrnei made m 
great Dumber of eipvriaients Qa the intiiuncc of the vairiflua ulu coniaJOLiI iu the 
Krum un the nbaarbing poncr ofthe blctdkl Tdf gii9C3. nis oh^trTnilioiui h&il pKP- 
tlcEilnr r^fcreni^ tv carbotiii; nciii, tlio eolnbilir^ nf tvLiL'h wiis inflHt'DLiiil euimi hj 
Kiiiiu: prindplce. Tti«se leiperimcnta vnru cunEnued uid extended b; LoHtaj 
Heynr il>li Gm* du Blitttf G^ltingon, 160?.) 



OASES Ell VENOUS AND AETFEIAL BLOOD. 457 

necessary to life, which is conveyed into the blood" ' excepting 
that the vivifying principle is not named nor its otlier prop- 
erties described, expresses what we now consider as one of 
the two great principles of respiration. This is even more 
fitrictly in accordance with fact than the idea of Lavoisier, 
who supposed that all the chemical processes of respiration 
took place in the lungs. Mayow also described the evolution 
of gas from blood placed in a vacuum.* Many observers 
have since succeeded in extracting gases from the blood by 
various processes. Sir Humphry Davy induced the evolu- 
tion of carljonic acid by raising arterial blood to the temper- 
ature of 200° Fahr., and venous blood to a temperature of 
112";* Stevens,' and others, disengaged gas by displaceraent 
■with hydrogen, nitrogen, or the ordinary atmosphere ; but 
in spite of this, before the experiments of Magnus, in 1837, 
many denied the existence in tlie blood of any free gas what- 
Boever.' 

Magnus made some experiments upon the human blood, 
extracting the gases by displacement with hydrogen ; but the 
oteervations wliich are most generally referred to by jihys- 
iologists were made upon the blood of horses and calves, 
extracting the gases by the air-pump, and giving the com- 
parative quantities existing in the arterial and venous blood. 
These ex]5eriment3 were of great value as settling the ques- 
tion of the existence of gases in the blood, either in a free 
state, or very loosely combined with some of its organic con- 
stituents; and until very recently they have been uuivcreally 

'Sec page411, note, 

* See quotation in Milne-Edwardh, Phytiohgit, tome i., p. 438, note. 

'Sia HcMPHRT 0ATY, Work*, Lonilon, 1839, yol, i., pp. 11-19. An £i$ay 
«n Lipkl, Hfot, and the Comhination of lAghl, mith a new Theory of Rapiration. 
*Loceil. 

* Gmelin, Mitseherlich, and Tiedcmann donicii the existence of any free gasca 
in the blood. At ono time Dr. John Tfaxj held tlic sainc opinion, thotigli lie 
finftllf recognized his error, and 8iiccecde<) in extmcling gas from the blood by 
meftnB of the tur^ump {Retrarthet, Pfiytiolaffical and Analomieal, London, 
18SS, vfA. ii., p. 1S4). 



458 



RESPiEA-noir. 



received by p])ysiologistB, as representing tbe relative propor- 
tions of tbe ga^es in tlae two Idnds of blood, thonj^li Ma^'Dua 
Btates in his paper tliat he does oot think he Bucceeiled in 
extracting all the gas tbe blood contained.' It is a question 
of the laat importance, as bearing upon onr conijirehen- 
sion of tbe es&ential protieeees of reispiration, to be able tr* 
determine tho relative proportion of oxygen and oarhonic 
acid in the arterial and venous blood. Until very reeently, 
our ideas on this sabject have bad for tbeir sole experimental 
basis tbe observations of Magnus, and in discussing the accu- 
rftL^y of the modes of analysis of the blood for gaees we need 
take no account of any experiments anterior to hi&, 



Anaii/ais of the Blood for Gases. — There are certain grave 
Bourcea of eiTor in the method euiphtyed by Magnns, wliieh 
rentier his observationa of little value, except as demonstrating 
tbnt oxygen, carbouic aeid, and nitrogen may be extracted 
by the air-pump from both arterial and venous blood. The 
only Boiiree of error in the results which lie fidly recognized 
lay in the difficulty in extrticting the entire quantity of gas 
in solution ; bat a careful fitndy of liia paper shows another 
element of inaccuracy which Is even more important. Tbe 
relative quantities of oxygen niid carlxinic acid in any single 
Bpecimen of blood present great variations, dependent upon 
tbe length of time that tlie blood has been allowed to stand 
before the estimate of the gases is made. As it is irapoeaible 
to make thia estimate immediately after tbe blood is drawn, 
on account of the froth prttdnood by agitation with a gas, 
wben the method by displacement ir employed,' and the 
bubbling of the gas when extracted by the air-pump, thia 

' Tim oH^nal B.rtic1e of Hnginui \» publEnheiJ in the AnnaUn der PAyaik unit 
Civinti! gf Po^j^fnilorlT, April, 183?, and is LraD«liite<l luto French ia tiie AtUL, dp 
Cld'iiie ft lif Phyx, or (he same ^cur,- 

' WIpb jws, such SB liyiir^^'L'ii, wLiuli \a not ronttiln^il in the Wtwl, Is iho^ 
oii^'il^i* mixvl with It l>j a^taiion la n closed re^el, it «ill p<»ctnit« Uie liquid, 
uid (liflplnce, OT driv? off; nit Che free gu which id held in solution. Thin U e»Ued 
the method of andj'sis hj cliGpli>cenieDb 




ANALYSIS OF 'THE BLOOD FOE GASES. 459 

objection is fatal. It is necessary to wait until tlie froth 
has subsided before attempting to make an accurate estimate 
of the volume of gas given off. Tlie following observation 
of Magnus illustrates this fact. The observation was on the 
hnman blood six hours after it had been thoroughly mixed 
with, hydrogen ; ' 



^oodi^lfan. 


Oarimtto add. 


4-0V7 cubic ioches. 


1-013 cubic indufl. 


8-6B0 " 


0-781 


8'888 


1-865 " 



After twenty-four honrs, at the end of which time the 
blood had no odor: 

4-07? cubic inches. 1-617 cubic inchefl. 

8-ft60 " 1-4B6 " 

8-838 " 2-075 " 

The excess of carbonic acid found twenty-four hours after, 
over the quantity found six hours after, in the first and third 
specimens, is a little over 50 per cent. ; while in the second 
specimen it is very nearly 100 per cent. 

In these analyses the proportion of oxygen is not given. 
The question naturally arises as to the source of the carbonic 
acid which was evolved during the last eighteen hours of the 
observation. This is evident, when we consider one of the 
important properties of the blood. A number of years ago, 
Spallanzani demonstrated that, in common with other parts 
of the body, fresh blood removed from the body has, of itself, 
the property of consuming oxygen ; and W. F. Edwards has 
shown that the blood will exhale carbonic acid. In 1856, 
Harlej-, by a series of ingenious experiments, found that 
blood, kept in contact with air in a closed vessel for twenty- 
four hours, consumed oxygen and gave off carbonic acid.' 

' 0. Uaqnus, 8ur la Ga» que eonlient U Sang : Oxi/ghie, Azote *t AeUie Car- 
botuque. — Annala de Chimk et de Pkytique, 2mc B^rie, tome liv., 1837, p. 174, 

" G. Harlst, The Chemittrtf of Bttpiralion. — Tltt British and Foreiffn Med- 
ito-CMTMTgieal RevUvi, Julj, 1856, p. 328. 



4G0 



nESpmAxiosr, 



More recentlj, Beroard bas shown llial fur a cerlatu time 
after the blood h drawn from the vessels, it will continue to 
(.'unsiune osjgeu ami exhale carboDic actd. If all the car- 
bonic acid lie reuioved from a epeeiuieu of blaoil, hy treatinp 
it with hydrogen, and it he allowed to sttrnd for twenty-foor 
hours, another portion of gas, can be removed by again treat- 
ing it with hydrogen, and Btill another quantity by tresiting 
it with hydrogen a third time.' 

From these facts it is clear that, in the experiment of 
Magnus, tbe excess of cai-bouic acid involved a post-mortem 
coneuinption of oxygen; and no analysea made in the ordi- 
nary way, by displacement with hydrogen, or by the air- 
pump, in which the blood must necessarily be allowed to 
remain in contact with oxygen for a nuinber of hours, can lie 
iiccurate. The only pro<M?Bs which can give ub a ri^irous 
eelimate of the relative quantities of oxygon and earboaJc 
acid in the blood is one in which tbe gaaes can be eaiiioated 
without allowing the blood to stand, or in which the formii- 
tion of cm'bouic acid In the specimeu, at the expfuse of the 
oxygen, h prevented. All others will give a Ick quantity of 
ox^'gen and a greater quantity of carbonic acid than exiiits in 
the blood circulating in tbe veesels, or immediately after it ia 
drawn from the body. 

A gotution of this bnportant and difficult problem in aiialy- 
Bi& of the blood has been accomplished by Bernard. This ob- 
Bervermade agreat number of exi^)erimeuts, id the liope of dis- 
covering some means by which the consumption of oxygen by 
the blood-cor]>u3<:]e'3 could be aiTested.'' He found, finally, that 
carbonic oxide, one of the uioat active of tbo poisonous gases, 
hud a remarkable affinity for the blood-corpuscles. When 



' ^EE)<i.BI>, Lk^iu itur le$ PropriiU* Fh^tii/laffiguM tl Iw ASiralitmt PuAoto- 
ffiguti dra Liqitk/m ffe T Orpimivat, Paris, 1839, lomei, p. 55* <f «if. 

* Darity (op. ciV.. |), SSi) os certain di {hw ft few ijnipt of cmorofnmi, mljed lo 
ll)t Frcsli bload. greatly diminiEhciI thu nitirity <if the cliuage of oi^jfeu liilo as- 
boQi£ bcliIi Ii did uot entirely mtc^i it, hoircrcr, and ibc author docs not ng- 
fvai iu UM in ciuautiutirc umly&ee for gttsc*. 



AHALVeie OF TOE BLOOD FOE GABE8. 



401 



laken Into the lungs, it ia absijrlied by and becomes flxed in 
the corjuidi'les, efl'eotuany preventing the toiisumption of oxy- 
gen and production of carbonic Jicid, Trhich iinmiiilly takca 
place in the capjllarj system, liod wbich ia one of ihe indU- 
peusable conditions of nulritiou. We have aln-'ady referred 
to the mechnnisiii uf pui&ouing by tho iiiUalattoa of tliiii gas, 
by its fixation in the blood-corpiiecles, their consequent pai^ 
alysie, and the arreet of their function as reepirntory orgiins. 
As it is the cuutinimnce of tijis traiistbrniatiu'n of oxygeii into 
carbonie acid, after the blood ia dniwn from the vessels, which 
interferea with the ordinary analysis of the blood for gaees, 
we might expect to extract all the oxygen, if we could imme- 
diately saturate the blood with carbonic oxide. The prelim- 
inary espminents uf Bernard en this point are cooclusive. 
He ascertained that by intxing carbouic oxidia in sufficient 
qnantity with a epeeinien of fresh artenal blood, iii sibimt 
two houi"3, all the oxygen wliiuh it contained was dis- 
placed, lutmdiieiug a second qnantity of carbonic oxide af- 
ter two hours, and leaving It in contact with tlie blood for an 
hour, a qufintity of oxygen was removed, bo small thnt it 
might almost be disregarded. A third experiment Ou the 
same blood failed to disengage any oxygen or carbonic acid.' 

The view entertained by Bernard of the action of car- 
bonic oxide in displacing the oxygen of the blood is, that the 
former gas has a reniartahle affinity for the blood -corpusclea, 
in which nearly all the oxygen ia contained, and when 
brought in contact with them unitea with the organic matter, 
eetting free the oxygen, ia the same way that the acid enter- 
ing into the compoBltion of a gait is set free by any other 
acid which has a stronger affinity for the base. There ig 
every reason to sappoae that this view ia correct ; as carbonic 
oxide 19 much less soluble than oxygen, and as it only has the 
property of disengaging this gas from the blood, leaving the 
other gases Btill in solution. 

A» carbonic oxide only diaplaceifi tlie oxygen, it ia neces- 

' BimKABv, Liiptliltt de r Ori/attitmt, lome i., p. STit. 
30 



462 



EESmtATIOS". 



finry to resort to eomc otlier pmcess, in nddition to thU, to 
diseii^;igu the uthur gases cotitained in the blood. It ife only 
neccfesiirj' to arrest the tiL'tion of the eciqiuscies upon the oxy- 
gen, luid tlieu the gases may he set tree hy the air-pump, or 
flny method whic-h (nay be troiivenient. The method adopt- 
ai hy Liitliar Meyer, IJeniaril. Liidwig, and ftrt-hant, fur the 
disengagement of all llie gases contsiineil in thu ]jl(.ii'djf3 first 
to displace the oxygen hy carUunie oxide, iiehig ahimt two- 
thirds of giis hy volume to one-tliird of blood, then to attAch 
the tnbe to a tube nf mercnry, tincl Bnhjcct the Wood to the 
barometi'ic vacuum, which sets free the carbonic acid and the 
nitrogen. The resulte obtained by this method correspond 
with our ideas concerning' the nature of the respiratory pro- 
cee& ; and aualy&og nf the hJood taken at ditfercut periods 
show variatioua in the quantitiea of oxygen in the nrti^rial, 
and carhoiiic Eieid in the Tenons blood, eorrespfindliig with 
6onie of the VflriiUione tthich we have noted in tlie loss of 
oxygen and gain of carbon ic acid in the air, in respiratirm. 
In drawing the blood for Bualysie, Bernard takes the tin id 
dircL'tly from tlie vessels by a syrinjrc, nnd passes it under 
niercnry into a tiibc, in snch n way thnt it does not come in 
contact with the nir. In this tube, wliicli h graduated, the 
blood IB brought in cyntact with carbonic oxide, wliieh dia- 
plaees the oxygen from the corpiieeles and prevents the for- 
mation of carbonic acid at the expense of a portion of the 
oxygen. The tube is tlien connected ivith an apparatus by 
wliieh the atmospheric preasure ia removed. In this wbj, 
nejiHy al! the gases contained in the blood are disengaged; 
but, according to most observers, a Bniiill quantity of car- 
bonic acid remains in tlie blood in enmbination. Thie may 
be removed by the introduction of a small quantity nf t^i^ - 
taric acid, II is justly remarked hy Bert,' in bin atbiurnbit 
work on respirfttiou, that, astheapp-imtus forilieeshan^tioi 
of air has been made mote and mure nearly perfi'ct, the 

> Bert. Lcfotu rur ta jiAytidoftt tmnjrarir dt fa fwpiralieis pMif, It) 

p. wa. 



AKALVSH OF THE BLOOD FOR GABE8. 4G3 

quantity of carbonic acid in combiuntiun has seemed Ices 
and less. By fur the greatest quaiitity of excreinentitious 
carbonic acid in the blood ia extracted by the removal of 
atmospheric pressure iu the most careful Iy-])erie;;ted ap^m- 
ratus. 

Tlie analyses of Bernard, wlio obtained from fifteen to 
twenty per cent, of oxygen in volume from the arterial 
blood, show tlic great im])crfection of the process employed 
by Magnus, who obtiiined fi"om the arterial blood of liorses 
and calves a mean of but 244 per cent, of oxygen. It does 
not seem nece6s:xry, therefore, to discuss the criticisms on 
the results obtained by Mnguus which were made by G.iy- 
LnsBae and Magendie, soon after their publication, and more 
recently by Ilarley and others.' 

Bernard's experiments were made chiefly on dogs, and 
had especial reference to the proportion of oxygen in the 

' As the re>>ult9 obtained by M;i{;nii!i nre (^encrnllj' quoted in worka nn |ihysi< 
fAogj, we (five the tablu, whii'li in tiLkun rnim tlic truintlation of bis ori^iuol 
■rticto in the Annnirs tie cUiink il ilr p/iiinii^iif (/w. cil.). We bav« not ttumirht 
it worth while to reduw tlio riduniofi fiinu ciiliic ct'titimetcre to cubic inchoe, 
U we add the percrntagc of gati in volume, which is not gircn by Uagous. 

{ n--) or car bonir acid, or4'))2 peruDL 
Btoodof hunt 126C.C. gave 9'Bc.c, of pu' in uroxyKvn, or I'M [lerevul. 

/ i^ 'it ullrciL'Pn, or atW *■ 



Vetxiua b1oo4l or the Mm«, ) i b"* »r c^irbunlc kl'IiI, or i"JV ft cent. 

1 12-2 c.c. of gas/ li-Sof nxy^a.nr 1*IJ piTct'Ot 
( I'l of nllniai'ii. oril.'-l ■■ 
I Ifl-i) of I'arhnuir acM. or frlS per eC 
H-i C.C. of gaa- lid nf oxj^i-n. ur W."- mt CKbL 



Id; of uierl«I bliwiL 
The umo blood 195 co. gave 



Art«ri«l blood of ■ bone 1 
Tery oid, but la suud VlSOco. gave Ifl-Se.&ofsM 
bealtb \ 



TImmdib blood \ii ccr. gavo]0-Sc.&or Baa- 



1(1-7 «r culuiik' ackt, or fi-M per cl. 
41 of iixyp-o, nrij'iri ii«r c*DL 
i-.'i of nliru)(i-n, or l-l.'> " 
71J of carbonli; acid, or (V'74 prr wnt 
i-i <iS ii\yil-.-D. m l-Sl iwroeut. 
l-Oorniirogeu, orO'Ai " 
Vmiddi liluod of Ihe samn I ( i^'4 of I'lirboiilc ntl'L or 7'20 per cL 

old bowe, dimwn three >n0c.cpiTol%t»c.fi.of(f»siS-5iifiix)-pin,orW7i>rrcfiiL 

d»f* ifter I ( 4it of iiltiiken, or a*! " 

( Vi ef rarbualu »fld, or 7*4 per ecnt 

Aitn^al UoiMl of coif ISSisc. caroUflcc. of cas-i :i-.1of o.tVL-.u, or i'-S4 ptnint 

(I'fiofQU^'J-'in. o'l'W *• 

i 7" of ciirlnnlc Bi'lil, or r>'49 [tcr cent 

Tbenma blood ll)ii>r.C garelS'tfcc. of pai< i-CuT oxygen, w'i-^' )kt ceou 

) i-n i.f iilirotvii, or i-i" ' 
TenoDi blood oflhe Bnine 1 ( in-.! uf carlunlc scld. or 6-W ftr cL 

caH taken four dnvB -I.^3 cc.g;ivvlS8«'.p.or pm- I'S "f nivti'ii. or l-ll iwrtviiL 

aft«r. .'., 1 I l*a of nltruKcn, oril'sS " 

I fi'1 of carbonic 3pM. or tSi pn ccufc 

rhe Mine bloud 140 cc gavu T'7C;C. of gas-v IHlof u\ytci:u,urU'71 jmtccui. 

( (h6 of nitroj^en, or 0*48 "* 



4(;4: 



HESPraATTOS', 



UiwJ, Ae far as we know, no analjses of the Lumau blood 
liave jet been raaile by liis metboci. In two specimens taken 
froTii a di>g in gvod condition, a speciuien of arterial liktud, 
drawn from the vessels bj a eyringo aod put in contact 
wlrli enrbonie oxide witbout being exposed to the air, was 
found to coiitaiu 18"28 per cent., and a speeiracn of venous 
blood, taken in the same way, S'i^ per cent,, in Tolome, of 
ox,vgtMi.= Tlie proportion of gases in the blood is. found to 
vary very considerably nuder different conditluuii of the 6ys- 
teai, particulaily with reference to the digestiTe process. 
Tlie following aj-e the general results of later observations, 
showing llie differences and variations in tiie proportions of 
all the gasGs, in arterial and venous blood.' 

Arterial Blood, while an aniinjd ia fasting, contains from 
nine to eleven parta per hundred of oxygen. In full digestion, 
the proportion is raised to Beventeen, eighteen, or even twenty 
parte perbucdred. The proportion varies in different anlinalsj 
being much gitatev, for example, in bii-ds than in mammula. 

The quantity of carboiuc aeid is even more variable than 
the quantity of oxygen. During digefitlon there are frona 
five to six i>ai-tB per hnndred ui' free carbonic acid in the 
arterial blood. During the intorvnls of digestion thi^ (juan- 
tity is it'dnced to almost nothing ; and after tasting for twenty- 
lour hours, frequently not a tnice is to he discovered, 

Venons Blood, always contains a large quantity of CAr- 
bonie acid, both fi-ee in solution, and combined in the forra 
of carbouates and bicarbonates. This quantity varies in dif- 
ferent parts of the venous system, and hears a relation to the 
color of the blood. It is well kno«Ti that tlie veuons Mood 
coming from eomc gknde is dark during tlie intervjde of 
Beeretion, and nearly as red as arterial blood during their 
functional activity. In the veuouB blood from the sub-max- 



' lae. eii., p. B6J. 

' Tlicee leauSta were girvn ia t. coune of Icclurce vrbicb wc bad ihn prinli:;;^ 
or bearing at the Cdlege of Fr.uii>e in the aumiucr of ISBl, and wbiDb liAie uol 
fct been poliliahed. 



SITROGEN OF TUE BLOOD. 



465 



illary gland of ft dog, Bernard found 1S*07 per cent, of car- 
bonic acid during repose, and lO'Ii per cent, during secre- 
tion. The blood coming from the muscles ia the darkest 
in tlie body and contains the gi-eatcst quantity of free car- 
bonic acid. 

The quantity of free carbonic acid is immensely in- 
creased in the venous blood during digestion. It is owing 
to this fact that the gas then exists in quantity in the ar- 
terial blood. 

Bearing in mind the fact that the proportion of gases in 
the arterial and venous blood varies considerably under dif- 
ferent conditions of the system, and that it is especially 
variable in the blood of different veins, we may take the 
following, wiiicli we quote from Bert,' as the average results 
obtained by the most recent German observers : 



CO, 



CO, 
Id comblBfr- 



CO, 
laM. 



ToIUiuIb 

Tgliuu.'! par 

IM. 



Arterial blood 
Venous' blood 



15-03 
817 



27-110 
31-^7 



ris 

2-38 



2014 
33-65 



1-60 

1-S7 



46-77 
43 19 



These facts coincide with the views which are now held 
regarding the essential processes of respiration. The blood 
going to the lungs contains carbonic acid, and but a small 
proportion of oxygen. In the lungs, carbonic acid is given 
off, appearing in the expired air, and the oxygen wliich dis- 
appears from the air is carried away by the arterial blood. 

Nitrogen of the Blood. — As far as is known, nitrogen has 
no important office in the process of respiration. There is 
flometimes a slight exhalation of this gas by the lungs, and 
the analyses of Magnus and others have demonstrated its 
existence in solution in the blood. Magnus found generally 
a larger proportion in the arterial than in venous blood, 
although, in one instance, there was a larger proportion in the 



• BiST, rkffiicloffU eomparie d* la rttpiration, PBria, 1870, p. 162. 



46C 



KEaPLRATlON'. 



venous blood- It is not absolutely certain whethof the nl- 
ti-cjgeu wliicli exist& in tbe blood be derived from tile air of 
i'miii the tiissuca. Its almost constant exlialution in the ex- 
pired ftii' would load ty the supposition that h h piv.duecd 
in emnll <j^iiantitj in the system, or supplied hy ihy food. 
Acwrdiiij^ tu Beruard, the q^iiautity of iiiti-ogeri in Ihc firte- 
rial blood is I'rom two to five parts per tliuuBniid.' It is pres- 
ent in nither smaller cjiiantity in the venous blood. There 
is no evidence that nitrogen enters into cumhiualion irith 
tbe hlood-coi'puBC'les. It esiste siniply in solution in the 
bloodt which is capablu of (ibsin-bing about ten times as 
much fls pure water.' i^othing is loiovvti with re^'arj to the 
relations oi' tJie tree nitrogen of tbe blood to tbe proo«»e3 
of uutrition. 

C'ondifion fif the Gases in the BJooiJ. — It is now pretty 
gDnemSly admitted tlint the oxygen of tlie blood exists, not 
in simple Bohition, but in a condition of feeble combination 
with the peculiar coloring matter of the blood-corpu^des.' It 
ia clearly demojistrated tbflt the corpuscles nre the elements 
which fix the greKte^t quantity of this gas. Carbonic oxide, 
which has a great affinity for the corpuscles, displaces almoet 
immediately all the oxygen wbieli llie blood coutjiins. Wbeu 
the eofpiist^les are destroyed, as they n]ay be reiidilv by re- 
ceiving fresh blood into a qnantity of pure water, the red 
color is instiintly changed to black. Oxygen in the blood 
bears a closer relation to the corpnsctes than that of mere solu- 

' UopublifliGd Icccurea dt^Hvorcd at tlie ColU'ge or FriDiae la Uie suniim 

Bf ISfil 

» Ii hufl luteh been eho^m tliat. (lie i-nlnrin? maUcr of Ihe eorpasulea, titt-nia- 
glAliitie, i\H9 rt r<:mavknb)t> nRlnily fiir fliy^cu, th«^ iiriidact of ills' union gr ox.y- 
gon and tlie uoloHsii* mnttfr in the OTtcriivl Ijlotwi Iwing ciiilsil cxyhreaitgldbinw. 
It lii:ri' lins n b^ri^lil-red cQlor, iiiid priJiMtd a eppi-lrum ditf.Tem hota ibal pro. 
dui'cd l\V [lip Polorinp tnnlfer iinconibiriuil wilh ftSTgun. TIiIb poini, wliich h«9 
■IrenJi" bi'on iiisL-usKil in connfeiion witli lh« cheroii.-*! ■cornpruitinn of tbe red 
bloofl-corpn&cSaB, hns an important benring up^n our kuoirJeJge of ihf ftiartioiia 
of llieae boiliea as osyjiea-cinTierj. 



c<»ri)tno» oe ths 0ASES i>' tub blood. 



467 



on. T]«e proportion which tlicy are captiblo nf cimtatiiiiig 
is to iL cei'tuiu df^roe absolute, and not depentknt npon plijs- 
icbI conditioua, sawla as pressure, wliieli invariably liave an 
iu:Suouce on the propovtiun of gas merely held in Bolutioii by 
licpiilfi. The projxjrtioii of oxygen in the blood c-timiot be 
iacreuded by pres&ure, nor is it dimiini-lied by reductioti 
of the ])ressiirei until It npproacLea a vhcuuiu.' The fact 
that the blood-corpuscles are capalile of consuming oxyj^eji 
and giving off ciirbonic acid is an additional argument in 
favor of the union of these anatomical eleniDnta with the 
gaSj thong'h tliis nuiou ia very feeble and easily disturbed, 
The plasma will absorb a certain quantity of oxygen, and ita 
aetiun in respiration seems to he intermediate; it first takes 
oxygen from the air and then gives it up to the corpngeles. 

Carbonic acid is more easily exliided frotn the blood than 
osygen. It was this principle which was obtained hy thoee 
who tirst fiucceeded in extracting gm from the blood. While 
there le every reason to suppose that oxygen in in C4>tuhiun 
tion with the blood-corj^usL'iies, a considenible proportion of 
the carbonic acid of the blood aeems to bo in a condition of 
simjile so]ntion,and is contained more especially fu the plas- 
ma. What may be considered as the free carb«jnic add of 
the LIockI behaves iii all re^'ftfds like a ^;is dimply held in 
solution. The view that this gas is held iu solution chietly 
in the plasma is adopted by nearly all modem writers.* 

Liel>ig has shown that the iiln.>s])hate uf eoda, one of the 
conBtitniints of the blood, ]ntinGnr.'eB to a reniarkablo degree 
the qnantilj of carbonic acid which can l>e hold in solution 
by any Hc[uid. One hundredth of a part of this salt in pnre 
water will double its capacity fui' dissolving carbonic acid.' 

' The f»(il thai oivgen is eiUalcd from the Mood in vacico is nol an nrfniiucct 
■gB.il>»l tlie vitw IhnL it'PiiLGra intofc'cblvcomhiaiitiDn with tlii? bl'iod'COrpiiiticlea ; 
for it is well kiioirn th»n rasny distinotly ret'ogiuzec] chcmiivLl ootnbiniitiiTns are 
disturbed by llic baiuc inpfliiti. For esmupli?, a racuiiiD La c^jmblic cf JUutigBgirig 
from fiomo of ihe (liearboiiutcfi rmn HK[UiTut'pnL ofoftrbtjnie aciJ. 

* Ronis, Lf^D/i iur In hnfnmrit^ Vavin, lfi74, p. 108. 

• 31iLXE.{^D«rARns, Ph^l^U, tOKie I., p. A^\. 



4e,s 



VSenRATKfS. 



Wlien rarliynic aeid. is formed by the blood, after it is (Imwn 
from tbo botly, it m immediately exhaled, at least in part- 
When lilund is in contact with a ccrtiiiii quantity of air, oxy- 
gen 16 consnmed and oai-boric add is exhaled. The fact tliat 
carbonic oxide, which has euch a remarkable affinity for the 
corjui sties, displaces osygexi aluioet exclusively, is aimther 
argument in favor of the view that the carbonic acid is con- 
tained iiiaiuly iu the plaRnia. 

A portioTi of the earbouic acid which is formed by the 
system unites with the carbonated lu the blood, particularly 
the carbonate of soda, to form hiearbonatM, is carried to tlie 
Inngs, and there set free by the pnetuuic acid. It here esieta 
in 90 loosu ft condLtioti of combination, thnt it may he die- 
engaged by ti-eating the blood with inert gases, or putting it 
under the receiver of ap air-pump. 

The carbonic ac-id which is funned in the tissues, and taken 
lip by the blund in its passage througit the capillariea, oxista 
in thiri fluid iu two forma : one, in siiuple solution, chiefly in 
the plasma ; aiid the other, in a state of eiith loose ehemii-al 
combination in the bicarbonutes, thnt it may he disengaged 
by displacement by another gas, aod is readily set tree by 
pneuiuit^i acid. Tiirs gas is a product of excretion, and is not 
engiigcd in any of the vital functions; while oxygen, whicb 
has an all-itu port ant function to perform, unites imntiHlialely 
with tlic blood- corpuscles, and U not eaftily disengaged, 
except when it undergoes tran-'formarion iu the prt)ces8 of 
autriliun. It is certain that all the carbonic acid in the blood 
ia not in corabination with bases, for the proportion of ^alts 
is not sattiiMent tu account for all the carbonic acid tliat can 
be disengaged. 

Ill iuldition to tliis exfreraenlilious earhonie acid, there 
is inuithcr portion which is a peruianent constituent of the 
blond, in the carbonates, and cannot be &et ft-eu without tha 
use of resgenta. 

Nitrogen exists in the blood in the same condition of sola* 
tiou iu the plasma as carbonic acid. 



MECHANISM OF THE INTEHCIIANGE OF GA8E9. 469 

Mechanism, of the Interchange of Gases heticeen the BJood 
and the Air, in the Lungs, — The gases from tlie air puss Into 
the blood, and the gases of tiie blood arc exhaled through 
the delicate membrane which separates these two fluids, in 
accordance with laws which are now well understood. The 
first to point out the power of gases thus to penetrate and 
pass through membranes was the late Dr. J. K. Mitchell, of 
Philadelphia.' His attention was first directed to this subject 
by noticing the escape of gas from gum-elastic balloons filled 
■with hydrogen. In order to eatiaty himself that the gas 
passed through the membrane indcpeudently of pressure, he 
put different gases in wide-mouthed bottles covered with gum- 
elastic, and by a series of ingenious experiments, which have 
become so common that it is unnecessary to describe them 
in detail, extended Dutrocliet's law of enJosmosis and oxos- 
mosis to the gases. lie demonstrated the same phenomena 
when he used thin animal membranes instead of the gum- 
elastic, and found that the more recent the membrane, the 
more rapid was tlie action. The rapidity of transmission was 
found to be very great in living animals. Observations on 
the lungs of tlie snapping turtle, tilled with air and placed in 
on atmosphere of carbonic acid or nitrous oxide, showed a 
very rapid passage of gas from the exterior to the interior. 
Dr. Mitchell recognized tlie psissage of gases through mem- 
branes into liquids, and tlic exhalation of gases which were 
in solution in these liquids. He noted this action in the ab- 
aorption of oxygen and the exhalation of carbonic acid in the 
lungs ; though he fell into the error of supposing that there 
was no carbonic acid in solution in the blood, and that it was 
exhaled as soon as formed." A few years later, Dr. Rogers, 
of Philadelphia, enclosed a frcsli pig's bladder, filled with 

• On the PendratU-eiuiit of F!md». By J. K. Mitchell, 3I.D., Lecturer on 
UtNlIcal Chcnii^trj in the Philade1]thU Medical Institute. Anteriean Journal of 
Ikt Mediral Si-ienat, Nov., 1830, p. 86, 

• Ibid., p. 6«. 



470 



BESrmATION. 



TPiimis blood, in a hell-plass of oxygeB.' In two honra n 
quantity of oxygen hail disupptarecl, and a largo quantity of 
Cflfbouic acid had made .its appearance. Dr. Rogers is fi"©- 
quently referred to ae the first to detnon&trate the pasftagt* of 
gasos tliroupli aiiiinal membranes to and from the Wood. 
The credit of this is due to llitt-hellj whoae pu|Hjr was pul»- 
liflheJ in 1&30, while the experiments of Eogcra were pub- 
liahed in 1H30. 

We have already seen that the hlood is exiH»sed to the air 
in the Inngs, separated from it only by a very delicate mem- 
brane, over an immense suriaee. The memhrane, far from 
iuterterhig with the int'pr.diange of gase*, actually favors it; 
and thus, in obedience to the laws which regulate endoamoais 
between gasea and lirjuids^ the osjgen is continually pafaing 
into the blood, and the free earbonie aiiid is exhaled. 

General Differences in the Composition <^ Arterial and 

YeuQUs BfomL—MX observere agree that there are certain 
marked differences in the compusition of artenal and venoaa 
blood, aside from tlieir tree giisee. The arterial blood eon- 
tains leas water, and ia richer in oi^niuj and moat inorganic, 
coTtHtituents tlian tlie venous blood. It also enntaina a greater 
proportion of red corpuscles and of inorganic eaUs. It ia 
more eoagiilable, and forms a larger and tirmer clot than ve- 
nous blood. Nnmerous analyses have fniled to detect a con- 
stant difference in the proportion of albuminoids ; soiuetiruea 
the proportion is greater in the vcuoiig, and sometimes in tbo 
arterial blood. The otilj principles which arc constantly 
more abnudaut in venone blood are water and the alkaline 
carbonates; but, although the proportion of carbonates, ao 
cordiug to Mitacherlich, Ticdejuann and Gmelin, and uthers^ 
is grcfiter in venoiie blood, the art(irial blood is richer in the 
other inorganic salt^. Tlie deficiency of ivater in the Idood 
whifh comes iVom the lungs is readily explained hy the 
escape of ivatery vapor in tlio expired air. 

• K'prriramti on thr BInod, ele, By RoDctiT P, ltoo»:ns. M.D., of riiit«i1*IpliSft, 
Amerira'i Jr^mnt of the MeiUntf Svtkm, .Vugual, ISSO, p. flflft. 

* LoMflET. Train A ph\jgio{ogit, Poria, ISflB, loiiie i., p. nof). 



DIFFEEENCES IN COMPOSITION OF BLOOD. 471 

An important distinction between arterial and veiioua 
blood is one to wbicli we have already incidentally alluded ; 
viz., that the former has a nniform composition in all parts of 
the arterial system, while the composition of the latter varies 
very much in the blood coming from different organs. Arte- 
rial blood is capable of carrying on the processes of nutrition ; 
while venous blood is not, and cannot even circulate freely 
in the syetemic capillaries. 



CHAPTER SIT. 



KELATlOira OF &EStIfiATIOET TO KUTSITION, fTO. 



^leWB of phj-siulogiata anterior to [lie lime of LoToisier'^licliilJons of l1ie coi> 
suTnptlon of oxT(;cn lo nutrittao — Itelations of tlie mJnilntioQ of mrtonio iciJ 
to nulriLioQ— EB-SGntial proceiieea of respLratioo — Tlie re.Bpipitory toofv, or 
wiuii on Die part ot the aytteiu trbk'h induves bbc ivspiraiar; mtiT«m«iit« — 
Location of tlie respiratoiy eenae in the general ftysifiin — Sense of »iifi<xatii») 
— RcdplTulor; cSbrtH before birtli — CutaneouB mj^irjition — Asphftik. 

It lias beeu demonstrated tiiat all tissues, so long as they 
retain their absolute integrity of composition, have, the prop- 
erty <jf ap])]"0]iriating oxygen ami exlmliug carbonic acid, iii- 
depenJently of tLc presence of blood; and tliat tJie nrterial 
blood curries oxygen from tlie lungs to the tissues, there gires 
it up, and receives earbonic acid, which is earned by tlie 
venous blood to the lnnga, to be exhaled. From this fact 
aloue, it is more than probuble that rospirntiuu is iuBejjarably 
ijonnected with the general act of nutrition, lU proccssea 
must be etudied, therefore, as they take place in the tissiiee and 
organs of the body. In the present state of the ecicnee, the 
HCietitions whieh naturally ariso iu (wnuectiou wi(h the estien- 
lial procesaes of respiration are: 

1. In TV-hat way 13 oxygen cunsHmed in the system ? 

2. lluw is carbonic acid produced by the syatem ? 

3. What k the natttre of the proccfscs which take pl»ce 
between the disappearance of oxygen, and the evolution of 
carbonic acid? 

"When these questions ai-e satisfaL-torily answered, we shall 
understand the e«Beuce of respiration ; but in reasoning on this 



HELATlOSa TO NtTTEITIOS'. 



4r3 



Bubject, Tre must not fall into the error of assianlatiiig the 
reepimtory phenomena too elosely to tkone with which we are 
acquainted as they occur in inorg'anic hodiee. Jt must he re- 
membered that in the organism we are dealing with prjuciplea 
which have tlie remarkable property of eelf-regeaeration; 
and whichj as a simple condition of vital exieteaee, cousunio 
oxygen, when it is prwented to them, aud exhale carbonic 
aeid. Without a proper PU]>piy of oxygen, the tiasuea die, 
lose these peculiiir properties, and finally dl&appear by putre- 
factive decomposition. This nonsnmption of oxygen caanot 
be regarded in any other light than as the appropriation by 
a living part, of an elenit^nt necessary to supply waste; in 
tlie same way aa those materials which are ordinarily called 
nutritive are appropriated. That waste ie continnally Roing 
on there can be no doubt; and as the production of urea, 
creatine, creatinine, chole&terine, etc., is to a certain extent 
independent of the al>6orption of food, bo the produclion of 
carlKonic acid is to a certain extent independent of the ab- 
sorption of oxygen. This has been fully demonstrated by 
the esperiroents of Spallanzani, Edwards, Geo, LieJiig, and 
others, who have noted the eshalation of carbonic acid in at- 
moepheres which contained no osygen. How diflferent are 
these phenomena from those wliich attend cornhinatione and 
decompositions of inorganic matters! As an example, let 
OJiygeu bo brought in contact, under proper conditions, with 
iron. Under these circu Distances, a union of iron and oxy- 
gen takes place, and a new substance, oxide of irou, is formed, 
which baa peculiar and distinct properties. In the aanitj 
way, carbonit; acid may be disengaged frotn its combinations 
by the aetion of a stronger acid, whicii unites with the bul^c 
and forms a new substance, in no way reseudjling the origi- 
nal Bait. To make the coiiti'ust &till more striking, let a hy- 
dro-carbon, liUe fat, be heated in oxygen or the air, until it 
undergoes combustion ; it is then cliaiiged into carbonic acid 
and water, by a dcSnite chemical reaction, and ia utterly de- 
slroved, as fat. 



i:4 



RESrrEiTlOX. 



In the living body tbe organic nitrriffenized principles are 
in a eoTidition of continual change ; breaking Jowii, and I'ono- 
ing vaiious excrementit.ioiig jji'incipl^v at the ln?ad of whicSi 
may Ijejjlaced carboak acid. It ia esaentitti tu lif« tliat Oiese 
pritidples be maiutained in their chemical jntegrity, which 
reipiirea a Biipjily of fresh matter as food, and above all a 
bu]iply of osygun. We put ourselves in the position of ig- 
noring well-estabUeltcd facts and prindplea when we nsetiuu- 
late without reserve the process of the coasnmption of oxygen 
and production of carbonic acid by living organic bodies, to 
Binjple cumbustton of sufiar or fat. Tbe ancieota saw thnt 
the U'eallj wiw wanner than tlifl surroundiiig air, that in the 
lungs the a\c took heat from tlicbody ; and aa they know of 
no other cbanges in the air produced by reepirntion^ they as- 
Buuicd that ita object was simply to cool tbo bluod. Lavoisier 
discovered thai the air, containing oxygen, lost a portion of 
this jirinciple in respiration, and gainwl earboiiic acid and 
wutery vapor. lie saw that tliis mighc be imitated by tlie 
combn&tioti of hydro-carbons, auch as exist in the blood. He 
called reapuation a slow combustion, nud regarded as ite prin- 
cipal g^oe tbe maintenance of animal temperature. WLea 
it was bIiowu by analyses of the blood for gases, tliat oxygen 
waB not ci>nsuiued In tlie lunge, but taken np by the circulating 
fluid, and carried all over the liody, nnd that corlmnic acid 
was brought from all parts by the blood to the lunge, these 
facts, taken in connection with the fact that the tissues have 
the propei-ty of consuming oxygen and exiialing carbonic 
acid, kd plijslologiatB to change tbe location of the coinbue- 
live process from the lun^ to tbe tissues, 

Vfe cannot stop at this point Kow It is known that tho 
organic principles of the body, which form the basia of all 
tieeucs and organs, arc continually undergoing change as a 
condition of existence; that they do not uuite with any 
Bubstunee in definite eheuiiijal proportions^ but their par- 
ticles, atler a certain period of existence, degenerate into 
excrement it ions substances, and they are regenerated by an 



HELATIONS TO NrTRITTON. 



475 



appropriation anO change of materials furuisliod l>)"llio blood. 
As tar aa tliu ree[ni'iiti(ju ol' tliuse piirta is L-oucemed^ ^ve can 
only say, that in this process, carbonic acid is produced and 
oiygeii i^ couaiiined. These CmitB show thnt respiration ia 
essentially a phenomenon of nutrition, po;Mft=sirjg a Uegi'ee 
of comjilexity equal to tliat of the other nwtntive proceasea. 
It must he actnowleiilgCLl that thus fur its cause and intimate 
nature have eJucItd investigation. In respiration by the tia- 
sues, no one has yet been ubie to give tbe cause of (he ab- 
Borptiou of oxygen or the exbiilatioii of carbonic acid; or to 
deninnstrate the condition in which oxygen exists when once 
approprifittid, or the pai'ticular ehaugcs which take iiIeico, 
and the principles which ar^ Eo&t, in the formation of carbonic 
acid. 

The views of physiologisla with regard to the esaential 
processes of respiratioiij before the time of Lavoiaier, have 
barely an historicid interest at the present day; e.\cept the 
remarkable ideii of Miiyow, which tJomprL-honded nearly tlie 
■whole proeesa, and which was unnoticed for about a hundred 
years,' It is not our object to dwell n}K>n the varions theo- 
ries whicli have been propoaed from time to titue, or even 
to tully diflcusii^ in thia connection, the eonilmstiou theory ns 
proposed by Lavoisier, and inodifiod by Lit-big und others. 
TLuugh this theory is nouiinjiily rec-eivetl l>y many physiolo- 
giats of the present day, it will be found that moat of them, 
in accordance with the facts wliit^b hare since been dcvoloi>ed^ 
really regard respiration as connected with nutrition. They 
only diiier from those who reject the conibustion-theory, in 
their definition of the tenn combustion. Lavoisier re};;arded 
res]iiratiou as a alow combustion of carbon and hydrogen ; 
and if every rapid or slow combination of oxygen with any 
other body be considered a eorabu&tion, thia view h abso- 
lutclv correct, and wn3 proven when it was shown that oxygen 
trniled with any of the lissuea, Longet says that since the 
time of Lavoisier it ia agreed to give the above signihcatioa 
'Seepage 41 L 



476 BE5PIBATIOX. 

to the word combustion;' but tliis mnsfeiraply be for the 
|turposc of retaining the name applied by Lavoisier to the 
respiratory proce^, while its signilicatioii is altered to snit 
the facts which have since taken their place in science. There 
is no doubt that combustion is generally regarded as signify- 
ing the direct and active union of oxygen with certain prin- 
ciples, which commonly contain carbon and hydrogen ; and 
the iranieiJiate products of this union are carbonic acid, water, 
and incidentally heat and light. It is certain that oxygen 
does not unite in the body directly with carbon and hydrc^en, 
though it is consumed, and carbonic acid and water are pro- 
duced, in respiration. Important intermediate phenomena 
take place, and we do not therefore fully express the respiratory 
process by the term combustion. The researches of Spallan- 
zani, W. F. Edwards, Collard de Martigny,* and others, who 
have demonstrated the abundant exhalation of carbonic acid 
by animals and by tissues deprived of orygen-f show that it 
is not a product of combustion of any of the principles of the 
orgauisni.' 

Kejocting this hj-pothesis as insufficient to explain the 
intimate nature of the respiratory process, it remains to be 
seen how satisfactorily, in the present state of the science, it 
is possible to answer the several questions proposed at the 
beginning of this chapter. 

1. In irhat ica>j is the oxygen con%urfted in the system. T — 
Oxygen, first taken from the air by the plasma of the blood, 
is immediately absorbed by, and enters into the composition 
of, the red cori>iiscle3. Part of the oxygen disappears in the 
red corijnscles themselves, and carbonic acid is given off 

' LoNOCT, Train dt Phgtiofofftt, Faria, 1868, toree L, p. 713, not*. 

* CuLLAiu) DE UiRTiGSY, Jieeherrhf* Eiperinienlalet tt Critiqtui ntr TAb- 
torptioii et lur FExJialation Jii*pirato!re». — Juumal de Phi/tuiogit, 1830, tome 
X.. p. lU. 

' Various olhor coii?idc ration a concerning the combustion-theorj of re^pin- 
tioD, audi as the so-called " respiratory, or caloriGc food," will be diacosaed Id 
conneciion with the aubject of Animal beat. 



COXSUIIITION OF OXVOEN. 477 

To how great an extent tliid takes jilaco it is impossible to 
Bay ; but it is evident, even irom a atudy of tlio methods of 
analyses of the blood for gases, that tlie property of absorbing 
oxygen and giving off carbonic acid, which Spallanzani dem- 
onstrated to belong to the tissues, is ]>osse3sed as well by th( 
red corimscles. During life it is not possible to determino 
how far this takes i)liice in the blood, and liow far in the 
tissues. Lagrange and ILijisenfratz ' advanced the theory 
that nil the respiratory change takes place in the blood as it 
circulates ; but the aviility of tlio tissues for oxygen, and the 
readhiess with which they exhale carbonic acid, leave no 
room for doubt that much of this change is effected in their 
substance. Tlie late ex])erinionts of lieniard,' showing tliat 
when blood is sent to the glands in large quantities, the 
oxygen is only imperfectly destroyed, the l>loo<l wliiuh is 
returned by the veins having nearly the color uf arterial 
blood, are positive evidence against this view. 

Oxygen, carried by the blood to the tissues, is appropri- 
ated and consumed in their substance, together with the nu- 
tritive materials with whitrh the circulating fluid is charged. 
TVe are acquainted with ponie of the laws which regulate its 
consumption, but have not been able to follow it ont and as- 
certain the exact nature of the changes which take place. 
It has been ascertained that oxygen luiites with the color- 
ing matter of the corpuscles; an<l recent expcrinicnts on 
this point have settled tliis fact beyond quet^tion. Some 
have said that it unites with the hydro-carbons of the 
blood and of the tissues; but there is more evidence that it 
enters into eombiuation cliietly with the organic nitrogenized 
principles. All that we can say definitely on this point is, 

' 11 ASSFSWRXTA, Jlfi moire »nr III C'-'inhinaifm df t Ozii^riic arte le (\vbimr H 
rifydroffeneilii SitH^,mr la DinAolutioH il( I' O^iji/hie if'iii.f le Sim^^ ct virl'i if'HiUre 
ionl le Calorique *r dr'^trrr. — AuH'tU* •!•■ Cliimii; ITDl, lnim- is,, p. LUil. 

' Liquiite* de V Onjauimitf, liiiiii- i. ; :iiul iiiiinibli.-lii'il Uvturi'^ iit tlie rotle-^e of 
France, ISfll. In the luier, Hfiiuril '•xws coiiijKirutive jiiial_vst:< of tlic vi-uoui 
blood from tho E>ui>iiiaxiUarv kI^'x'i j«1iMwing a lar}^<r prui>oitivn uf oxv^lq iluriii); 
lu AiDctiooal activilj tlian duriug rcpnao. 
31 



478 



KESPIBATJOK. 



tlint it. nnites with tlie orgniiic principles of the sptem, satis- 
fying the *' rt-spiraLury stiise," and supplving an iiii|M?rative 
want wliich 13 felt by all aiiiinalfi, oiid extends to all parta of 
the orgaoism. After being absorbetl, it is lost in tlie intri- 
cate procea&e^ of nutrition. There ia, no evidence in favor of 
the view that oxygen unites directly with carbonaeeons mat* 
ters in the blcod wliich it meete in the lungs, and, by direct 
uniou with cai'bon, funna carbonic acid. 



3. Ham is carbonic acid produced hy t/te system f — 
That carbonic acid makes its appearanc-e iu the blood it- 
Belf, produceil in the red corpusfles, has been abundautly 
proven by observations already cited ; tbongh it ia impos- 
sible to determine to what extent this takes place dnring 
life. It is likewise a product of the physiological deeoiopo- 
sitton of the tiBsues, whence it is absorbi-d by the blood uir- 
ciilating in the capillarieB and conveyed by the veins to the 
right eide of the hewt. It has been experimentally demon- 
Btrated that its production is not immediately dependent 
iipiin the absorption of (isyj^n ; for it will go on in un atmos- 
phere of hydrogen or of nitrogen. It is most reasonable to 
eonHidor the rarbonic acid thus formed as a product of «• 
crelion or disiiSBimJlation, like the nrea, creatine, or cliolcp- 
tei-iue. The fact that it may Ciislly be pn^^duced artificially, 
out of the l>ody, does not demonstrate that its fonnation 
in the body is as simple as when it is fornieil by the pro- 
ceaa of combustion. We may be ablo at some future time 
to produce artificially all the excrementitioua prineiplw, 
ae I1113 already been done in the case of urea ; ' but we are 
hardly justified in Buppoatng that the mode of formation 
of this principle, aa one of the phenomena of nutrition, is 
precisely the same aa when it is made by our chemical ma- 
nipulations. 

' Waller Gmt Ibrm&l iirca aitlfldaUy by k imlatk at eyaaiv blIiI kkX wok 
inonla. SiiiC(> l.hL-n it hd.^ bci.'ii pn>]iarL'i[ by chtuDisU (ij VAiicms pnccKM 
(L£im»S)f, Pkifno!ag>etl CfimiiMtrif, PliUuiJetpllift, 1S6S, voL i., p. l»7l 



EESPmATOET BEN8E. 

Afl espressiiig nearly all tlmt is known, even at tlie pre*- 
eut day, regarding the mode of fbnnatioii of carbonic acid 
in tlieec:unoiuj,we may take the following concluding passage 
from the paper of Collard de Martigny, published in 1830 : ^ 

"The carbonic acid exjiired ia a product of aesitniluihc 
(leco]/>j}09itioTij s^-creted in the capillaries and excreta by the 
langs." 

The carbonic acid thus produced is taken op hy tbe 
blood, part of it in a triie state in aolutiou, particularly in 
tbe plasma, and n part \pbich has united with the cai'bonatcB 
to form bicHrbunates. Curried time to the luugs, tbe free 
gas is removed by nimple dieplnceinent, and that which 
exists in eoitiliiamtion is Bet free by the nelda found ia the 
pulmonary substance, 

3. TTZfli ts i/te nature of Oi^ mU^meillate preciii9e4,from 
the disdjfpearance of oxy^ffn to the evofvtioii of carhrmla 
acidf — A definite answer to this question would uompEeto 
our knowledge of the respiratory process ; but this, in tlie 
pr^eutetate oftliescience, we arenotprejiai-ed to give, We 
can only repeat what has already been bo frequently referred 
to, thut osygeu must be considered ne a nutritive principle, 
and carbonic acid a product of excretiou. The intermediate 
proteoses btlong to tho ge^rmral fimt-tioti of outiitioti, with 
the intimate n.iture of which we iire uBacquainted. "We 
have not sutEcient evidence for supjjosing that this proceaa 
is identical with what is generally known as coinbnstion. 



The H^^pii'atof't/ &mag' or Want on the part of the Si/iteta 
■which induces the R^^irator>j Mov^nenta. {Besoin -Ic 
r&tpirer.) 

We are ftll familiar with tbe peculiar and distrGssintj 

* Loc. ciU, p. 160. TliL' author ftJds : " Tbe chcmtca) llwors of LsvoinitT, 
fif KSpintiuu, ia B gmtuitaus supiiositioru Tliin runctlon should bic cciiLai[ii'it.-U 
U a c6m]ilL-Ie icnd of kclit ofgenefal iLSslmibtiou." 



4S0 



eenee of siifiFooation -wVnih. attends an iQtevriiptioii in rtio ffr 
epiratory procees. Under ortHnarj conditions, tlie act of 
breathing takes iilsice without our kno\vIe(lj;e; but even 
when the air h but little vitiated, when its entrance into the 
lungs IB slightly intcrftirtd with, or wlieii a eonsiderEble 
portion of the pnlmomiry structure is involved by diseasG^ 
we experience n certain st-nac of nneasiness, and beeotne coii- 
Bciousof the ncceBsity of rospirfttory efforts. This gpaduallv 
mergea into the sense of euffocation, and, if the obeirnction I»e 
sufficieiit, is folloived by convuUions, insensibility, and Cual- 
ly by death. 

Thougli we are not sensible of any want of air under or- 
dinary conditions, it was proven by the celebrated experi- 
ment of Robert Hook, in Idfii, thnt there ja a tt*ant nlwHVS 
felt by the syetem; and thnt if this want be effectually sup- 
plied, no respiratory movementa will tnke plac'ij. We have 
otleii repeated tbe esperiment demonstrating this fiift. If a 
dog bu brought L'orapletely under the influence of etber^ the 
rhest and nbdonacn opened, and artitielal respiration be 
carefully kept up by means of a i>cllowa fixed in the trachea, 
even after the nTiinml has eonie from under the influence of 
the anaesthetic, so as to look around and wag hi& tail urlien 
spoken to, he will fi-eqnently cease all respiratory move- 
ments; when tiie air ia pi-operly supplied to the Inngfi. This 
fact can be very satisfactorily observed, as the diaphragm 
and other important respiratory mnsdes are denuded, and 
exposed to vie^v. Tf the artihclHl respiration be interrupted 
or imperfectly performed, the animal almost ininiediiituly 
feels the want of air, and the es[»o6ed respiratory muBclefl 
aro thrown into violent but ineffcsotnal contraction.' 

It l& generally admitted, indeed, that there exi&ta in the 



* For full details of Ihi^e Ctpeiitnetils Oip rcOclL-r ii wi^hnvA lo AD srliclr l>? 
the AuLhor, ciltitlii<<l Stpfrimeiilal Snirarchfs on PoinI* fonnFiird fifh thr Ariiim 
of iKe U^'ri and tuilfi linpiralion (Amcr Iran Jour nicl of l/ie MfJieai Srienr^, Uul., 
ISfll}. Sini'u tKa puVjlicolion gf this pn]ier, ib« oiperimL'tiu on resiwciou Ua\f 
Ikwh Oequootlj rvpenloil pubUclri and ihe Dosclueions vnifiinl. 



EESPIKATORT SENiJP. 



4S1 



Byatcm what may n|jproijri!itely be calletl a resphatorij sena^, 
or, as it is called by the Freueh, lesoirt tic reitjtirer, wbidi ia 
conveyed to tlie resjjiratorj nervous centre and gives ri&o to 
tlm onliuary reflex and involaiitary uioveinente of respira- 
tion ; tLat tliia sense \& exaggerated liy m\y thing which luiei"- 
fercs with re^piratioo, and is then earrit-d on to tlie brain, 
where it \& appix^cicttm] as dvapnoja, aud tinally qa thu over- 
powering goose of finflbc-ution. An exaggeratiuu of the 
i"OSpiratorj eenoe uoustituics au oppression, ^vhich \% rtl'erred 
to the lungs. It ha& been demonstrated, iiowever, that tlie 
sensation of hunger, wLiuh is felt in tlio etomach, and of 
thirst, which is I'eit in the throat and fimees, liave their seat 
really in the general fljiiteiii, and ai'e instinctively referred 
to tlie parts mentioned, becfiiise they are severally relieved by 
the introduction of food into the stomach, and the paesage 
of liquid along the throat and Gfooi>Uagus. It taunot thei'e- 
fore be assumed, frutii sensations only, that the sense of want 
of ah- lA i-ually located in thu luugs. The t[ue8tion of ila seat 
and its immediate cause ia one of the most iutereatiug of 
tho6c coiniected with reb^Hiratiun. 

ilany physiologists accept the view of MarslinU Hall,, who 
firet accurately described the reflex pitenonieua, that the re- 
spiratory sense is located in the lungs, Is carried to the medulla 
oblongata by the pulmouar/ branches of the pnenmogastric 
nerves, and is due to the acenraulation of carbonic acid in the 
pulmonary ■scsiclea ; but there m-u faut^ in physiology and 
pathology which lire inconbistent with such an exclusive view. 

In cases of disease of the heart, when the system m im- 
jierfectly supplied with oxygenated blood, the sense of fluttbua- 
tion is freqnuJitly most distressing, though the Inngs be imiif- 
fected, and receive a siiftlcient supply of pnre air. Tiiis and 
other Bimilar facts led Ecrard to adopt the view that thu 
iVflpiratory sense has its point of departure in the right cavi- 
ties uf the heart, and is due to their dietcutloii as the reeult of 
obstruction to the passage of blood through the lungs.' Johu 

' BiiuRp, f/intivloffit, tome iii.| p. 028. 



182 RE8FIBATI0X. 

Eeid thought it was due in a measure to the circulation of 
Tenous blood iu the medulla oblongata.' ^hnt has been 
shown to be the correct explanation was given byVolkmann 
in 1841. He regarded the sense of want of air as dependent 
on a deficiency of oxygen in the tissues, producing an im- 
pression which is conveyed to the medulla oblongata by the 
nerves of general sensibility. By a series of experiments, this 
observer disproved the view that this sense resides in the lungs 
and is transmitted along the pneumogastrie nerves ; and by 
exclusion, he located it in the general system, and showed that 
Buch a supposition is competent to explain all the phenomena 
connected with the respiratory movements.' In the hope of 
settling some of these questions, which might be regarded as 
somewhat uncertain, we instituted, a few years ago, a series of 
experiments, which were embodied in the paper already re- 
ferred to.' In these observations, the following facts, some of 
which had been previously noted, were demonstrated ; and 
their results leave no doubt as to the location and cause of 
the respiratory sense : 

1. If the chest he opened in a living animal, and artificial 
respiration be carefully performed, inflating the lungs suffi- 
ciently but cautiously, and taking care to change the air in 

' An &ptTimenial Inveti'^aiion into the Function* of iht Eighth Pair of 
Nerva, etf. Fart second. Anatomieal and Ph^ioloffital Retearcha, Ediiv- 
bui^b, 1848, p. 26S ; and Edinburgh Medical and Surgical Journal, 
April, 18S9. 

^ VoLKHASN, in Schtnidi't JahrbHeher, 1842, p. 290. Tolkmum Bhows that 
adcr division of tbe pueumogostrics, an animal dies when deprired of air, not 
calmlj', but wilh undoubted HjmptomB of distress from suffocation, ae if it had 
bi'CD strangled without previous dtriaion of tbe ra^. Be alao made a number of 
eipt'riments, in which respiratory efforts continued fur many minntes after eztir- 
paiion uf the lungf>, in cats and dogs, care being taken to leare (he phrenic nerrca 
iitlAct. Be goes on to reason that the sense of want of ur must reude in the gen- 
eral system, that it is due to a dcfii-icucj- of oxygen, and that its exaggeration 
constitutes the sense of suffocation. His observations do not show, however, 
that this is not due.tu the presence of carbonic acid, as has been supposed by 
many. Vierordt is of the opinion that the resforatory sense ii due to the drcu* 
tation of ibc Tcnoua blood in the substance of the uervea. 

* Amtriean Jourinii, October, 1861. 



BESPmATOBY SENSE. 483 

the bellows every few moments, as long ud tliis is continued, 
the animal will make no respiratory effdrt ; showing that, for 
the time, the respiratory sense is nlwlished. 

2. When the artificial respiration ia interrupted, the respi- 
ratory muscles are tlirowu into contraction, and the animal 
makes regular, and at last violent eflforts. If we now expose 
an artery, and note the color of the blood tis it flows, it will 
be observed that the respiratory efforts commence only when 
tlie blood in the vessel begins to be dark. "When artificial 
respiration is resumed, the respiratory efforts cease only when 
the blood becomes red in the arteries. The invariable result 
of this experiment seems to show that the respiratory sense is 
connected with a supply of blood containing little oxygen 
and charged with carbonic acid to the systemic capillaries by 
the arteries, and that it varies in intensity with the degree 
of change in the blood. 

3. If, while artificial respiration is regularly jierformed, a 
large artery be opened, and the system be thus drained of 
blood, when the hseinorrhage lias proceeded to a certain ex- 
tent, the animal makes i-espiratory efforts, which become 
more and more violent, until they terrauiate, just before 
death, in general convulsions. The same result follows when 
the blood is prevented from getting to the system by applying 
a ligature to tlie aorta. 

These facts, which may be successively observed in a 
single experiment, remain precisely the same if we previously 
divide both pneumogastric nerves in the neck ; showing that 
tliese are by no means the only nerves which convey the 
respiratory sense to the medulla oblongata. 

The conclusions which may legitimately be drawn from 
the above-mentioned facts are the following : 

The respiratory sense has its seat in the system, and is 
transmitted to the medulla oblongata by the general sensory 
nerves. It is not located in the lungs, for it oj^rates when 
the lungs are regularly tilled with pure air, if the system be 
drained of the oxygen-carrying fluid. 



184 



XESfHUTlOX. 



It is ihic to a want of oxyj^en on tlie part of the eystem, 
and not ti) any faiicieJ irritant properties of carljonic BL^d; 
for w3ien tlie lungs are filled ■ft'itli air» and tlie Bystem is grad- 
ually draiaed of blooiJ, ihougli nil tlie blood which fiiidg its 
way to the capillaries is fully oxyyenated^ as tlie qnantity 
becumcs insufficient to supply tlie required aniotint of cxyjrcn, 
the sense of wnnt of air is folt, and respiratory efforts take 
place. Tlie eijveri mental i-esults ou which these couclnsiMiis 
aj-e based are invariable, and bare been deoionetrated re- 
pcatetlly ; bo that tlie localion of the re9i)iratory sense iu tJie 
general systeai, and the fact that it is au espressiou of H^-ant 
of oxygen, seem aa tertain as that oxygen is tal<en up by the 
blood frotn the lungs, aniE distributed to the ti^uen by the 
arterieB. AVith tliis view we can explain all the reflex pli&- 
nomena which are conueuted with the respiratory function.' 

The supposition of Berard that the respiratory scnac i& 
due to distention of the right cavities of the heart is disproved 
by the simple experiment of sudden excision of this, organ. 
In that ea,se, as the ejsteni i« drained of blood, etfort« at 
respiration invariably take plaoe, thougli the supply of air to 
the lungs be c^ntinucil, 

SeJi6e qf Sttffocatimi. — ATe must separate, to a certain 
extent, the reajjiratory eenee from the sense of distreaa from 
want of air, and its extreme degree, the sense of stiffiication. 
The tii-et is not a sensation, Lnt an impression eouvcyeJ tv 
the medulla TiUyiigata, giving Hae to involuntary reflex move- 
ments. The neceesities on the part of the syHtem fur oxygen 
regulate the supply of air to the Sungs. Wo have already 
seun that every fivo to eight respiratiouB, or when tlie reapi- 

' Tlicrc on; toony [ibcnDtucua wluLh pli>'siiili>i,-iBti founit it Impoi^tMc lo ex- 
pliiiD on llicpupposilion tliiil tlie " htKiin Jc raipirer" was locittcl iu (lit lungs wiit 
ciinrcycd to tbe uieJulIn oLilon^u bj tlir |iiiuumog«i«(ri(x ; Huang wliitk mar 
he mcQilfcnisl the rSbct of iniuiiriu of lite gk'iicml fiiirfftce in tlic reeiuduiion nf 
aew-born cliildrcu in wUlclli tvS|»i™iioii is not caUibllsluij eitoiiUnMiiAly. I>r. 
UaraliuU UiilE nnil Jolin Hdd Uiougbt lliat in lliesu cusua tbc scusorj flUmrnU cIIjb 
tribiit«<i oQ the skLn had aomclliLii;^ to do in IrntiaiiLitliu-; iuiprcs«ion« Iu Ui<.* Tt«[it 
ruorj ocutre. 



BEN8B OF SUFFOCATION. 485 

ratory movements are a little restricted under the influence 
of depressing emotions, an involuntary deep or sighing in- 
spiration is made, for the purpose of changing the air in t)ie 
lungs more completely. The increased consumption^f oxygen 
and a certain amount of interference with the mechanical 
process of respiration during violent muscular exercise put 
ns *' out of breath ;" and for a time the respiratory move- 
ments are exaggerated. This is perhaps the first physiological 
way in which the want of air is appreciated by the senses. 
A deficiency in hfematosis, either from a vitiated atmosphere, 
mechanical olwtruction in the air-passages, or grave trouble 
in the general circulation, produces all grades of sensations, 
from the slight oppression which is felt in a crowded room, 
to the intense distress of suffocation. When haematosis is but 
slightly interfered with, only an indefinite sense of oppression 
is ex])erienced ; the respiratory movements are a little in- 
creased, the most marked effect being an increase in the 
number and extent of sighing inspirations. In the experi- 
ments upon animals to whicli we have referred, when artifi- 
cial respiration was interrupted, we first noticed regular and 
not violent contractions of tlie respiratory- muscles ; but as the 
sense of want of air was exaggerated, every muscle which 
could be used to raise the cliest was brought into action. In 
the human subject in this condition, the countenance has a 
}>eculiar expression of anxiety and distress, and the move- 
ments soon extend to the entire muscular system, resulting 
in general convulsions, and, finally, insensibility. 

Bearing in mind the fact, that though these sensations 
are referred to the lungs, indicating increased respiratory 
efl'ort as the common means for their relief, they have their 
real point of departure in tlw geiieral system, we can under- 
stand the operation of various abnormal conditions of the 
circulation, when the lungs are adequately supplied with 
fresh air. The first subjective symptom of air in the veins 
is a sense of impending suflTocation. There is no want of air 
in the lungs, but the circulation is instantaneously inter- 



4SG 



BESPtniTIOK. 



nipiecl, niid oxygeiiiited liluod is not 8ujii>Tieti tu the tis- 
sues. Thu finiiiie effect, ].inifticall}', tViiluwB abstraclittii of 
the circTilatiiig fluid, or the absorption of anvpoisouous agent 
whidi (leetruiys. the function of the eorpusdes ns carrfers of 
oxygtu ; though in bieinon'liage^the efl'i^cts are not a& luarkod, 
ae generally tho system is gradually debililiited by the pn^ 
grt-^&ive loss of blood. It ivas iiivarliibly noticed in the cx- 
imninenta above referred to, that jiftur the divibion of a hirgo 
artery, thmigb artificial respiration wna carefully pLTformed, 
respiratory eflbrte took place when the .BTstem ■was nearly 
drained of blood. At! thehiLTnorrhageeontiiincd, tliesc crt'orta 
became more violent, and terminated, just before death, in 
general convulsions.' A coraparison of this expennicnt with 
those in which artifioinl respirjition "was eimply internipteil 
shows that In Biidden hieuiorrhage there can be do doubt tlint 
the system feels the want of oxygen ; and when the ttjse of 
hlood is. very great, this is increased nntil it anioimts to a 
fienee of snffociition. In gradual hsemorrhage, there is a con- 



' " JScpt xiiiT., Fi-b. IP, 186 L A goi>d-M7.ed dog was ellieriied aud the diusl 
o[M"neil in theii<<iittl wlj. AfUflfiiil t-ciAptraUoD wm i^ubliAh^d, aad Bipl. xxix. 
veriQi^. Thi> bloi)d wjis then uUonBiI to fioi> fnc\y IVom llic rcinoral atUfj. 
wUil* artilitiiil rcSjiimtioii wa3 atlivelj coiitiaiied WliUe tlio IdtHKl cotitintioil to 
flow, Iho rc^piTfttury musL'Ica witi* cnTL'fuIlv oliscrvcd. DurinB; the first jiort of 
tli^ l>k-(.'<liti|j; no reHpimtury ofTurtK tuuk |ilni<i;; bul wlira the blual ha'i f'lvnl far 
a eohnidiTufdr lirjrr, aitrf the tifltnn t^nt fieeivnhif ilrtniieii, ret/irrifforv eJf'irU (■»»• 
piriictil, /tfMe aljir»t., but at ihn titfjwtf ty'iitiiivnil, b^'oimirip fntirt cwtenl uitlil tAt 
vholc tiiUKutiir tifit'.f'i 11^4 offtid'eii On arnvvlitive »ici*rrn«nlii." (Am, Jeum., he 
ciK, 11. 3JB.) 

L'unTulaions nlU-r prol'iao tiwrnorrii.igo liave Ion? been obMired by phj«o}- 
ogiBb., but na cui.irely ivatiafaclnrT ex|ilanivtion of iIwit Dceurrciice has c^isr Nmd 
^ven, Tl)«^n> nnw cnn be no doubt tint thc-j ilk: iluc to a deliciency ororrgen. 
The eT[»ritBiyitfl of Ki^sniiiiE and Tenner (0« tfie Nattim and Origiu of Epi!r]A 
firm C«»i^uUcoiii titiuefl fry /Vu/W Jltcrdin;/. New SvilcDhun FociH;, Loniion, 
ISSO] slmvr tlint ixinmliiiuiis tuny bv |irui] ui-cil b_v ll^lure of thu gcvat fcalt-ll 
cntTjiQg MiKid to thubtmici. In this caae tliey are prtiliably due lo a Jelitkiicy of 
oiygun ill tJib vascnlup anil iilglilr oiffnoizcd pjirL. Iti tlieir Ktiierinjiait*, wblcll 
wiinjiDHilu tfci ra Wills, il Kna tibsLTvyil tint ■'KspiraUou i^ at fi«t »cc»^lci»iffl3. b"* 
shurtl.v adXi^n^^nJs, u little wbilc before tlio apfiractcb of gGHcral wdvu1^oq*i '■ 
bocuniLiJ proluDgL-d uiiJ dvep." F. 14. 



BEepnuToav eftobts bkboss bibth. 



4S7 



eervative proWsmn of Natiu-e, by which faintnc&a and diuii- 
nutioii in the force of.tbe lieart's action fftvor tlie arrest of 
the flow of blood. 

Poisoning by carbonic oxide is generally flcpoirpanied with 
conmlaii'Ds, wbich ame from the seiK^e of suffcK^ation, atid are 
due to a iixatiun of this gas in the blood-corpuscles, by which 
they nre rendered incapable of giving oxygen to the system. 
Convulsions also attend poisoning by hydrocyanic ucid, in 
caaes in which the fivstein is not overpowered iimnediately by a 
large dose of this agent, and the mijRcidar irritabilily di\stroyed. 

Experiments have failed to show that the respiratory 
Ben&e, or the sen&e of &uffoeation, is due to irritation produt^ed 
hy carbonic acid in the non-oiygcnaled blood. 



Respiratory Efforts lefore Birth. 

It b generally admitted that one of the most important 
funetioDs of the placenta, and the one whieh is most im- 
meiliately connected wilh the life of the fwtus, is a rcapini- 
tory interclianf;;e of i,'ase8, analogous to that whicli takes 
place in tho gills of aquatic animals. The vascular pro- 
longations from the ftetus are continnally bathed in the 
blood of the mother, and this is the only way in which it 
can receive oxygen. Notwithstanding the etatements of 
thofie wlio have been onable to note any difference in color 
l)etween the blood contained in the niiibilical arteries and 
the vein, there are dii-ect observations showing that sncli a 
difl'erenco does exifit. Legallois frequently observed a liright 
red i;olor in the blood of the uiubihcal vein; and nji alter- 
nattdy compressing and releasing the vessel, lie saw the blood 
change in color gnceeaeively from rod to dark, and dsu-k to 
red.' Ab oxygen ia thus adequatcdy supplied to the system, 
the fcetus is in a condition aimilar to that of the animals in 
which ortiiicial rcB-piration was efle<.'tually performed. The 
want of oxygen is fully met, and tlierefore no rc&piralory 

' DisAXD^ Ctiun de Fhyiioioffie, U>mc ili., p. 4S&. 



488 



BESriKATlON, 



efforts take place. Respirittory movements will take pl«<*, 
howevei', even in very j'tniTij; aniinAU, when tliere is a *lti6- 
cieiK'T ol' 03:jgen in the eystem. It lias been obacrvefl tliat 
the lii[uof amiili uceasionally finds its way into tbe ivs-pini- 
tory passiiges of the t'tEtiis, where it could only enter tn ettbrns 
nt reepii'ittion, TVioslow, in the latter part of the luat cen- 
tury, ttret notic'&d respiratory eti'orts in the fiEtu&es of enta 
mid tings, in the uterus of the mother during life ; ' and many 
otbera have obeerveil that when ftctusea are removed fi-oni 
vast-ular L-onnection with the motlier, they will make rij^or- 
ous etfortfi. at respiratinii. This fatC we have tipcqneiuly hnJ 
occasiou to demonstrate in making operations upon pn^tiant 
antTOfllg. After the death of the mother, the foetus always 
makes a certain number of respiratory effort6^ which are not 
uncertain iu their charactw, but distinct, accompanied by 
great elevation of tbe ribs, opening of the mouth, and follow- 
ing each other at regular intervals, independently of irritaliun 
of the general Buriace,' 

From what htia been experimentally denaonstrated with 
regard to the situation and caufio of the rMpiratory sense afttr 
birtli, it is evident tliat want of oxygen h the caaae of ro- 
epiratory movements in the fcetns. When the circulation in 
the maternal portion of the placenta is interrupted from any 
cause, or when the blood of the fintus is obstructed iu ita 
course to and from the placenta, the irapresfiion due to thy 
want of oxygen is conveyed to the medulla oblongata, and 
efforts at re^piratinn are the result. This cannot he due to 
an accuTQ Illation of carbonic acid in the lungs, and is entirely 



' Briiith and Foreiffn ifmliifo-Chtniryieal Jieoieu, April, 18A4, p. 890, 
' \V>: takii from uur uulobook ibg following ob^i.'rvKUoii sliowlcig neiiimlury 
tfforti ill a very vouot; miiiiinl ; 

"Juu, C, IS^D. Ill o]>*-''^^''ilj Unluy onasmiUl«lieilliii(;!i, (iir[lic|iurpOHvr 
ituioi>a^lmi1ng ihc glyt^DgcuiL' pi'iH.vsd in Ike ll*'er, I foumJ bet i^repiAnl. uid la 
llic ut4:riia mtre eii pups, ccrlninly not more thitn onc-foiiitli llic siu chiich ilic^ 
■.ttajn lieftjirc birth. {Tiwj were four inches bug-.) On rfoioTing them fmm lUa 
womb, tuiJ ijiviiliiig Ihe uutbili'L-al Tu»i^l», Uu'y nil inndv • number of profvunrJ 
resiniraturj vfibrts ait iaUirv&Itt of tmxu tttu b> tbrov niioulo*." 



CUTANEOUS EESPIEATION. 489 

eonaistent with our views, locating the respiratory sense in 
the general Bystem.' 

Cutaneous Respiration. 

Tliia mode of respiration, though very important in 
many of the lower orders of animals, ia insignificant in the 
human subject, and even more slight in animals covered 
with hair or feathers.* Still, an appreciable quantity of 
oxygen ia absorlwd by the akin of the human subject, 
and an amount of carbonic acid, which is proportionately 
larger, is exhaled. Exhalation of carbonic acid, which is 
connected rather with the functions of the skin as a general 
excreting organ and is by no means an essential part of the 
respiratory process, will be more fully considered under the 
head of excretion. Carbonic acid is given off with the general 
emanationa from the sui-facc, being found at the same time 
in solution in the urine and in most of the secretions. It is 
well known that death follows the application of an imper- 
meable coating to the entire cutaneous surface ; but this is 
by no means due to a suppression of its respiratory function 
alone. The skin has other ofBc^, particularly in connection 
with regulation of the animal temperature, which are infi- 
nitely more important. 

An estimate of the extent of cutaneous, compared with 
pulmonary respiration, has been made by Scliarling,' by com- 

* The phrsiolngic&l and pitliological qucstiona connected with the subject of 
*' rcspiratioD before birtb," are &bly and cxhau^tiTcly di^usdod in a revicn" pub- 
lished in the MetUco-Chirurffical Btvieic, for April, 1861. A number of ex- 
petiments by various observers arc here detailed, fully wtablisbing the facta we 
have stated. Among the most intcreating arc those nf Schwartz, showing respi- 
ratorj movements in fcctuses, when care was taken not to expose them to the 
cool air or any other irritation of the general surfacp, p. 338. 

* Rkokault and Reiset found the cutaneous respiration so slight in tbc ani- 
■nals which they used for their experiments, that ita influence upon the compo> 
rition of the wr in which they were confined could be disri^^ded. (Op. eit) 

' In HlLXE-EnwABiie, Lefont tur la Pki/ridogie, tome ii., p. 636. The reader 
wQL here find an account of the expiiriments of De Milly, Abemethy, and others, 
daaooBtntiiig the absorption of oxygen and exhalation of carbonic add by the skia 



490 



EISPIRATION. 



]mrin<» the reliitive cjutiiititieri o!" cnrboiim acul exiialed ia the 
twenty-four horn's. According to Ihifi tibserver, the akin 
performs from. -^ tf^ ^ of the respiratorj foncttoiL 



AgpAyxia. 

The efTectB of cutting ofl' tlie supply of oxygen from the 
liinga are mainly referable to the circulatory system, aiid 
have already been considered under the head of the influence 
of respiration upon the circulation.' It will be retnenihei^d 
that in asphyxia tl)e non-aenited blood passes with bo much 
difficulty through the systemic capillaries, as finally to arrest 
the action of the heart. It m the experience of those who 
have expeiTjneutecl on this subject^ that the niovementd of 
the hoiirt. once arrested in this way, eannot be reBtored ; but 
that while the slightest regular itinvenieTits continue, ita 
fiiiictiunB will gradually return if iiir he readmitted to the 
lungs. 

A reniarkahle power of Teaieting asphyxia exiatsinnewly- 
bom aniinalg that have never breathed. This was noticed by 
Haller and othei*, and hoa been the snbjeet of numerous 
experiments, among which we may mention those of Buffon, 
Legallois, find W, F. Edwartls. Legalloi* found that young 
rnhbita would live for fifteen miontcs dejirived of air by 
Biibniei'sion, but that thiB power of resiatance dimiuiKhed 
rapidly with age.* W, F. Edwards has shown that there 
exhtti a great ditl'erence to this regard in different classes of 
ftnimals. Doga and catd, that are born mth the eyes shut, anil 
in which there is at first a very alight development of animal 
heat, will show signs of life after submersion tbr more thaa 
half an hour; white Guinea pigs, whith atebcm with theeyes 
open, are macli more active, and produce a greater amount 
of iieut, will not live more than seven minutes.* 

' See pot'<t 21't>. 'Pefl pure 421, nwle 

* W. F. F.nvriuiD3, De Plajlufnce dm A^eni PA-i/fi^wt tur la VU, I'wb. 1D9^ 

pp. HI, 172, 



Asi-nvxiA. 



4'Jl 



Tlie cause of this peculiarity lias Iieen atlributeii to the 
existence of the tbramoTi ovaU>, enabling the blond to gi;t 
t<i the syatem without paasing through the Iimge, by those 
wliu regard the arrest of tlie firculation in asph_vsiaas f)uo 
to obstruction to the pulinouary circulation ; but this expla- 
imtinn is not sufflcieut, as blood passes easily throujrh the 
liirn^ in asphyxia, and ia obstructed only in the eyatemic 
capillaries. 

Tho true explanation seems to be, that in moat warm- 
blooded animaU, during the very first periods of cxtra-uterino 
life, the demands on the part of the system for oxygen are 
comparatively hght. At this time there is very little activity 
in the processes of nutrition, and the actual consumption of 
oxypen and exhalation of carbouic acid are very much below 
the regular standard in animals of this class. In [act, their 
condition id somewhat like that of coldddooded animals. The 
actual difference in the consumption of oxygen imineJiatety 
atler birth and at the Jige of a few dnys id sufficient to explain 
the remarkable power of resisting asphyxia just after birth. 
The coraparali^e observations of Edwards cm dogs, cats, and 
Guinea pigs, bUow that this power beaJ"8 a definite i^ehition 
to the respiratory activity. 

One of the uioBt interesting questions, in a practical point 
of view, con nectcfj with thefluhject of asphyxia, is tho effect on 
the system of air vitiated from breathing in a confiried space. 
Thtrc Hi-e here several points presented for eonsideration. 
The effect of respiration ou the air i^ to take away a certain 
proportion of oxygen, and add certain principles which are 
regarded as deleterious. The emanation which is generally 
regarded as liEiving the most decided influence upon the 
Byatera is cftrbomc acid, 

A careful review uf the moat reliable observations, on thia 
Bubject shows that the influence of carbouie acid ia generally 
Tery much ov.:'r-tstimated. In poisoning by charcoal fumes, 
it is gcnemllj carbonic oxide wlucli is the active princi- 



4!)3 



RrapmATioy. 



pie. Re^'uault AuJ Rciset' exposed dogg and nil)l>tt4 for 
many Iiours to an atmnB|»bere coutainiug 23 parU per 101) of 
carhuiiiu uciil arn'tiL-iiilly lutrcKloL-ed, and. 30 to 40 parts of 
oxyi^en, without nny ill effccta. Tbev took care, liowever, 
to keep np a roiiijtant supply of oxygen, The^-e exjieriniciita 
are at variance with the resxilts obtained by others, but Re- 
gnatilt and Rei&et explnin this difiereuce by the siippot-ifion 
liiot tlie gasiee in olUer oliserv^atious were probably impure, 
cuntuiiiing a little chlorine or carbonic oxide. There is no 
reason to doubt, from the high reputation of the obeervere 
for skill and accnrncy, that their experiments are perfectly 
reliable; and in that case, tliey prove that earlwnic neid does 
not act upon the gystem as a poison. This view ia Buataiuod 
by the more recent observatiuns of Bernard with c&rbumo 
oxide, whieh is known to be eseeegively poisonous. In ani- 
mals killed by this gas, the blood, both venous and arterial, 
is of a bright-red c-rdor, whleh is due to the ftxatcon of Urn 
gas by the blood-corpnscIcs. In this way, the red corpuscles, 
wbtch act noncfllly as respiratory agents, carrying oxyj^n lo 
the tissues, are pai-ftlyzed, and the aidmal dies from asphyxia. 
^Ve have already referred to this remarkable al^nity of the 
red corpuscles for carbonic oxide, and its action in arresting 
the transformation of oxvfren into carbonic aeJd in the blood, 
in treating of the difterent methodB nf amdysis of the blood 
for gases, and have shown that this gas is the proper agent 
to use in the method of analysis by displneement.* 

In breathing in a confined ^pac-e, the distress and tho 
fatal results are produced^ io all probubiUty, more by animal 
euiauations and deficiency of oxygen, tliau by tlie ]iresonce 
of earbonic acid. When the latter gas is removetl fts fast ns 
it is produced, the effects of diminution in the proporliun iif 
oxygen arc soon very marked, and progreasively infreflBO till 
death occurs. Bernard hits Ghomi that birds cnrlosed in 
a confined apace, from which the carbonic aeid is carofoHy 



/!)«. fit 



* Sec pt^ tOl 



ABPHT31A. 



49S 



removed, will gradually conBume osvgen, tiiitil, "wKeti ile&th 
occurs, the jrroportion is reduced to from 3 to 5 parts per 
100.' Wlien tlie carbouie acid is allowed to remaiu, the 
iiiereased Jeii&ity of tlie atn]ioBphea*e iatorfcres with tlie dif- 
fuaion between the gases of tlie blood and the air, and death 
BuperTenes with greater rapidity. 

The inflaence on animaU of emanations from the Inngs 
and general snrfiice is undoubtedly very considerable ; 
and tliia fact, which aluiost all bave expyriwQced moro or 
less, has been fully and paiuJully illustrated in several 
inatanccB of lar^'e numbers of persona confined, without 
proper cliango of air. Overcrowding is one of the most 
prolific sources of disease among the poorer claasoa of &o^ 
ciety ; and there are many fomia of diBcaGe prevalent in 
large cities, that are aEmost unknown tn the rural dis- 
tricta, and tliat can be alleviated only by proper sanitary 
regulations, which, unfortunately, are often very difficult 
to enforce' 

In crowded assemblages, the slight dimiDUtiou of oxy- 
gen, the elevation of temperature, inereaae in moisture, 
find partlculsrly the presence of organic em.inatioDB, com- 
bine to produce unpleasant flensatioDB. The terrible et- 
fecta of this cirried to an extreme were esomplifled in the 
cuiifinenicnt of the 146 Englibli prisoners, for eiglit hours 
only, in the " Black Hole " of Calcutta ; a chamber eighteen 
feet square, with only two eraall windows, and those ob- 
Btrncted by a verandah. Out of this nnmber, 96 died in 
sjy houre, and 1*^3 at the end of the eight hours. Many of 



' Qer^vard, L«pm» »ur Ira effeli da m6«laner» toziqnei et rncdieamenleutn, 
Paria, 18S7, p, lie. 

' In the rural dbtricta, iDL'n are able to perronn on nnomit of Imrd U^mt 
wltEch is impDHsible la o1<i?S, pT^obuljIv on gi;c'[)iiDt of diQt;n:iicee in ilicl ildiI 
Oib-fr enriiurr ondilions. f'arm-liuiuli) frtijuenily bcgia wurk m Biinribe, and 
liilmr, with uliplit it}fcrmi6'!*if)n.s uniil suiniJot, wliile ceu lioura ia cmnsiiierpd a 
gooii Jiiy'a work in oiiica \ but these men generullT liaTe aa abund&nce of g<*d 
food^ nnd are nciC ob1ii;cd to uleep in u confined space. 
33 



BB8PQUTI0N. 

those who i mm od lately survived afterward died of potrid 
fever,' This fin'ghtful tragedy lias t'rc(|uently beea re]>e»ted 
on. eniigrant and slavu sliips, lj_y euntiuiiig gr